Glossary of morphological terminology of adult Syrphidae (Diptera): an update and extension

Abstract

An updated morphological terminology for adult Syrphidae (Insecta, Diptera) is presented. The need for an update and extension of the terminology became evident while preparing species descriptions for the European Commission funded Taxo-Fly project on European Syrphidae. The scope of this paper however is worldwide. The manuscript describes the method used in finding as many relevant terms as possible and also discusses the use of the preferred terms, e.g., based on novel insights on the wing venation and division of some of the thoracic segments. The main part comprises numerous figures depicting different body parts with terminology indicated on each figure. A glossary of all terms used is given in alphabetical order. In total 17 photos and 207 drawings are presented, depicting almost 400 terms. A total of 14 new terms are introduced to more accurately describe the different body parts of adult Syrphidae. A short description for each term is given, together with additional information such as synonymous terms.

Full text

Glossary of morphological terminology of
adult Syrphidae (Diptera): an update and
extension
Jeroen van Steenis, Gil F.G. Miranda, Tamara Tot, Ximo Mengual
& Jeffrey H. Skevington
ISSN 2949-6748 Volume 2 No. 4 2023

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1
Journaal van Syrphidae 2(4): 1–99 ISSN 2949-6748
https://www.syrphidaeintrees.com/jvs/
Article
https://doi.org/10.55710/1.AIMS1978
https://zoobank.org/References/ 412906AC-7943-409E-8441-A6490164B380
Glossary of morphological terminology of adult Syrphidae (Diptera): an
update and extension
Jeroen van Steenis1*, Gil F.G. Miranda2, Tamara Tot3, Ximo Mengual4 & Jeffrey H.
Skevington5
1 Syrphidae Foundation, Schaepmanlaan 2, 3741VC, Baarn, the Netherlands. Email:
jvansteenis@syrphidaeintrees.com. https://orcid.org/0000-0001-9231-1516
2 Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-
Food Canada, K.W. Neatby Building, 960 Carling Avenue, Ottawa, Ontario, Canada, K1A
0C6. https://orcid.org/0000-0001-7919-2639
3 University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, Trg
Dositeja Obradovića 2, 21000 Novi Sad, Serbia. https://orcid.org/0000-0001-8776-9362
4 Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut zur Analyse des
Biodiversitätswandels, Adenauerallee 127, D-53113 Bonn, Germany. https://orcid.org/0000-
0002-6185-9404
5 Carleton University, Department of Biology, 1125 Colonel By Drive, Ottawa, ON, K1S
5B6, Canada. https://orcid.org/0000-0002-1445-9870
*corresponding author
Received: 09-05-2023 Accepted: 08-09-2023 Available online: 02-10-2023
Handling Editor: Francis Gilbert
Abstract. An updated morphological terminology for adult Syrphidae (Insecta, Diptera) is
presented. The need for an update and extension of the terminology became evident while
preparing species descriptions for the European Commission funded Taxo-Fly project on
European Syrphidae. The scope of this paper however is worldwide. The manuscript
describes the method used in finding as many relevant terms as possible and also discusses the
use of the preferred terms, e.g., based on novel insights on the wing venation and division of
some of the thoracic segments. The main part comprises numerous figures depicting different
body parts with terminology indicated on each figure. A glossary of all terms used is given in
alphabetical order. In total 17 photos and 207 drawings are presented, depicting almost 400
terms. A total of 14 new terms are introduced to more accurately describe the different body
parts of adult Syrphidae. A short description for each term is given, together with additional
information such as synonymous terms.
Keywords. hoverfly, flower fly, morphology, new terminology, glossary of terms.

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
2
Citation: van Steenis J., Miranda G.F.G., Tot T., Mengual X. & Skevington J.H. 2023. Glossary of
morphological terminology of adult Syrphidae (Diptera): an update and extension. Journaal van
Syrphidae 2(4): 1–99. https://doi.org/10.55710/1.AIMS1978
Introduction
Since the work of Speight (1987) on the terminology of adult Syrphidae several attempts have
been made to standardise the morphological terminology by publishing glossaries (Thompson
1999; Skevington et al. 2019) based on revised terminology as published in several Diptera
manuals (McAlpine 1981; Vockeroth & Thompson 1987; Thompson & Rotheray 1998;
Rafael & Skevington 2010; Cumming & Wood 2017). Other authors have introduced syrphid-
specific terminology (Doczkal & Dziock 2004; Reemer & Ståhls 2013a, b) applied to a
specific genus or subfamily. Hippa & Ståhls (2005) determined the external morphological
characters of adult hoverflies useful in phylogenetics using a mixture of terminologies. In the
most recent summary of morphological terms for Diptera, Cumming & Wood (2017)
proposed different terms for similar features, such as fascia for general lines, bands for
transverse lines and stripes or vittae for longitudinal lines. However, several characters also
found in Syrphidae were overlooked, such as antennifer, cicatrix, fossette, and notal wing
lamina.
The Taxo-Fly project, funded by the European Commission, was the motivator to
update the works of Speight (1987) and Thompson (1999), and to produce an extended
glossary of morphological terms used in adult hoverflies. Taxo-Fly is devoted to developing
taxonomic tools for European species of hoverflies as a resource for the European Union
Pollinator Monitoring Scheme (Potts et al. 2021).
Material and Methods
The adult morphological characters used for the present glossary were taken from several
species to show the diversity of the features to make it more easy to recognize these in other
species too. For each term the Latin or latinized version was preferred as stated by Thompson
(1999). The orientation of all body parts in relation to the plane is given as anterior or
posterior, lateral or medial, basal or apical, and dorsal or ventral. The terms used for each
character were checked against known publications on Syrphidae, and thus each term in the
glossary has a reference for its literature source. Morphological terms are listed in
alphabetical order to facilitate their search. Several synonymous terms are listed alongside the
preferred terms, with the preferred terms in bold. In order to check their current use in
Syrphidae and other families or groups of insects, and to see how the different body parts are
illustrated, several websites and handbooks have been consulted (Harbach & Knight 1980;
Grimaldi & Engel 2005; Saigusa 2006; Yeates & Hastings 2010; Gordh 2011; Sorkin &
Herman 2018; Dessì 2019; Geller-Grimm et al. 2021). The terminology of the structures of
the female postabdomen in Syrphidae are from Kotrba (2000) and Miranda & Moran (2017).
The specimens used for this research are from the following collections, with
acronyms in parentheses: California Academy of Science, San Francisco, USA (CAS);
Canadian National Collection of Insects, Ottawa, Canada (CNC); Coleção Zoológica do
Maranhão, Caxias, Brazil (CZMA); University of Guelph Insect Collection, Guelph, Canada
(DEBU); Faculty of Sciences, Department of Biology and Ecology, University of Novi Sad,
Serbia (FSUNS); Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil (INPA);
Coleção Entomológica do Museu Nacional do Rio De Janeiro, Rio de Janeiro, Brazil (MNRJ);
Museu de Zoologia da Universidade Estadual de Feira de Santana, Feira de Santana, Brazil
(MZFS); Naturalis Biodiversity Center, Leiden, the Netherlands (NBC); private collection of

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
3
Jeroen van Steenis, Amersfoort, the Netherlands (JSA); Zoological Institute of the Russian
Academy of Sciences, St Petersburg, Russia (ZISP).
All figures are made by JvS, except for those figures made by GFGM, TT or taken
from published literature, indicated at the end of each caption. In the text and table each figure
is hyperlinked to the corresponding figure, by clicking on the bold faced figure number. Line
drawings made by JvS were made with the aid of a drawing mirror attached to a
stereomicroscope, sketched with pencil and traced with ink. After scanning, the drawings
were edited using the GNU image manipulation program (GIMP version 2.10.32). The wings
and terminalia were drawn by GFGM using Inkscape 1.1, and manually tracing over extended
focus TIFF images of specimens generated by Leica Application Suite software from images
obtained with a Leica M205C stereomicroscope. The line drawings of the body orientation
(Figs 1 and 2) and the thorax in dorsal view (Fig. 24) were made by TT using high quality
photos, which were sketched with a pencil and traced with fine liner pen on tracing paper
using a HUION Graphic tablet A3 Led Light Pad, followed by scanning and editing in Adobe
Photoshop® version 10.0.
The photos were created by JvS with the aid of a DSLR camera and stacking software
as outlined in Bot & van de Meutter (2019) and van Steenis & Wyatt (2020).
The list of morphological terms and the list of specimens used for the figures can be found as
supplementary information on the website of the Syrphidae Foundation
(https://www.syrphidaeintrees.com/jvs/volumes/volume-2-4/) under “Volume 2 No 4
supplement 1 and 2”. In the list of specimens used to illustrate the present work, the locality
information and the authorship of the species are included and this information is not repeated
in the figure captions. In the glossary many genera and species are mentioned as examples. In
order to keep the glossary as compact as possible no author names are added after the specific
epithets, instead the authors of these epithets can be found in the supplementary file of species
used for the illustrations.
Results
The suggested terminology, presented in bold face, of the present work is based on previous
terminology. Several concepts are updated and redefined (clearly stated for each term). Some
body parts were never named and a new term is introduced when the structure differs from the
surrounding area.
The Latin or a latinized version of the structure, as adopted by Thompson (1999) has
been used for the majority of terms; however, for convenience we have kept the English
equivalent for some concepts, e.g., facial tubercle instead of facial tuberculum, postmetacoxal
bridge instead of postmetacoxal pontis, postpedicel instead of postpedicellus, or suture instead
of sutura among others.
In total, 16 terms are introduced here for the first time. Some new terms are derived
from previously used terms and they identify structures for which there is no proper
terminology. We explain the new application or definition of these terms in our glossary.
Twelve of these new terms are the following: antevertical sulcus (Fig. 9B); frontal tubercle
(Fig. 15B); malar tubercle (Figs 11B, 12B, 13B, 14B); mediotergal suture (Fig. 27B);
metapostnotal tubercle (Fig. 29B); notopleural sulcus (Fig. 29A); occipital tubercle (Fig. 8A);
paravertical sulcus (Fig. 9A); pseudo-mystax (Fig. 15B); temporal tubercle (Fig. 15D);
vertical carina (Figs 8D, 9C), and vertical sulcus (Fig. 7C).
The remaining four newly introduced terms more precisely indicate structures that
differ from other parts of the body. These terms are antevertex, mala, M4 base and
paravertica. These four terms are explained here with the reference to the figures given in
parentheses.

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
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- The antevertex (Fig. 9B) is the area on the dorso-medial part of the head present in
some species in which the male is dichoptic. This area might be homologous to the
area with frontal rugae in females. The antevertex is bordered by two transverse sulci,
the frontal sulcus and the antevertical sulcus.
- The mala (Figs 12A, 12C, 12D, 13, 14A, 14C, 14D, 15B, 16D, 17C, 17D, 22) is a
term for the anteroventral part of the face, between the face and gena. This area does
not seem to be a truely separate structure but it has a distinctly different texture from
the rest of the face and thus warrants a new term.
- M4 base (Figs 34A, 37C) is a vein closing cell bm in the antero-apical corner
connecting the following three veins: vein M4, crossvein m-cu and vein M-M2.
- The paravertica (Figs 8B, 9A) is situated on the frons and it is seen as a longitudinal
depression along the eye margin medially bordered by a punctured integument.
The term hair is not used here as we prefer to use the Latin equivalent pile instead.
Mammals are characterised by their hairs and body coatings but other animals like birds and
fish have their own specific terms, i.e., feathers and scales (Dhouailly 2009). In insects, no
such specific term could be found, so the latinized translation of hair, i.e., pilus, is used as
suggested by Thompson (1999) and already used more than 150 years ago (Rondani 1857).
Thompson (1999) used pile as the basic term and even if this does not seem to be a Latin
word we prefer the continued use of this word. Pile is referring to the hairs on the body
“thorax with yellow pile” the condition of having “hairs” is pilose and the singular is pilus.
The often used terms ‘front/fore’, ‘mid’ and ‘hind’ for the legs are considered
subordinate to the terms ‘pro’, ‘meso’ and ’meta’ as adopted from Thompson (1999) to
indicate the origin of the locomotory organs and to locate the nearby pleural segments (e.g.
prothoracic, mesothoracic and metathoracic). In order to avoid confusion with the locomotory
organs of larvae, the prolegs, in adult terminology it is advised to use the singular proleg. The
terms fore, mid and hind are not rejected, but the use of pro-, meso- and meta- in the legs
seems more consistent with the use of these prefixes in the pleural segments like proepimeron,
mesonotum and metakatepimeron.
We follow Thompson (1999) regarding the body orientation by looking at it in three
planes: the horizontal, sagittal and transversal planes. This makes four pairs of terms possible:
anterior-posterior, apical-basal, dorsal-ventral and lateral-medial.
For the terminology of the wing two systems have been in use for the last three
decades. The system generally adopted in several of the Diptera manuals (e.g., McAlpine
1981; Thompson & Rotheray 1998) is regarded as the old one. An alternative terminology
was established shortly after (Shcherbakov et al. 1995; Wootton & Ennos 1989; Saigusa
2006) and introduced to a greater audience in Cumming & Wood (2017), who suggested
considering it the standard. Here we adopt the alternative terminology instead of the
traditional system as it reflects the true origin of the basal veins more correctly (see Cumming
& Wood 2017). The changes that follow from the new insights are:
- cell a2 is now cell a1 (Fig. 34B)
- cell cup is now cell cua (Figs 34B, 36D)
- cell a1 is now cell cup (Figs 34B, 36D)
- cell cua is now cell m4 (Fig. 34B)
- crossvein bm-cu is now crossvein m-cu (Figs 34A, 37C)
- crossvein bm-m is now M4 base (Figs 34A, 37C)
- crossvein dm-cu is now crossvein dm-m (Figs 34A, 35, 36, 37C, 37D)
- vein CuP is now pseudovein (Fig. 34A)
- vein CuA1 is now vein M4 (Fig. 34A)

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
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- vein A2 is now vein A1 (Figs 34A, 35A, 35C, 35D, 36B, 36C)
- vein CuA2 is now vein CuA (Figs 34A, 35A, 35C, 35D, 36A–C)
- vein A1 + CuA2 is now vein CuA+CuP (Figs 34A, 36A)
- vein A1 is now vein CuP (Figs 34A, 35B, 36A, 36D).
The words cell, crossvein or vein are used in the glossary, but these terms do not have
a specific illustration in the Figures, where we refer to the different cells by their name (e.g.,
br, dm, r4+5), or crossveins (e.g., h, m-cu, r4+5-m1), or veins (e.g., C, R1, M4). A vein may have
an additional small vein, here called appendix, and their name is sometimes written in full,
like appendix of vein R4+5, or as appendix R4+5.
As outlined by Snodgrass (1960) and adopted by Nayar (1964) the term sulcus instead
of suture is used for the lines or grooves present on the face, as employed by Doczkal & Pape
(2009). A sulcus is an invagination of the exoskeleton while a suture is a line separating two
or more sclerites, so in the thorax most of the grooves are indeed sutures. Speight (1987) and
Thompson (1999) discussed that sulcus is a groove/shallow depression on the exoskeleton,
and although the former corrected ‘transverse suture’ to ‘transverse sulcus’ (as preferred by
us), the latter kept the traditional term. Here the view of Snodgrass (1960) is adopted and
most of the grooves on the head are sulci and those on the thorax are mostly sutures.
The surface structures of the body and the pilosity of the calypter and thoracic
spiracles have not been studied in detail and the associated terms are mostly not added to the
glossary. For a detailed study of the body sculpturing see Harris (1979) and for pilosity see
Hippa & Ståhls (2005).
Some of the terms given in the glossary are membranous structures not easily visible
in drawings, especially in the male and female terminalia, which need further study. The
figures of the postabdomen (Figs 43–46) are shown in either dorsal or ventral view. The
orientation of sclerites VI–VIII and the terminalia are not necessarily in the same plane as
these structures are rotated to a large extent.
Despite the illustration of most terms used in the glossary, it is likely that other
structures present in adult Syrphidae are not studied here. Several of the terms as given in the
glossary are combined terms, such as the combination of tibia and carina in the term “tibial
carina”; a narrow definition is given as it seems restricted to the apico-ventral part of the
metatibia. If there were a carina on any other tibia or place on the tibia, the term “tibial
carina” can still be applied but with reference to which tibia and its placement on the tibia.
The terms are classified into a section with general terminology and other sections for each of
the main body parts: head, thorax, wing, legs, abdomen, male terminalia and Female
terminalia. Below we provide a list of figures depicting all the terms in each category and
when terms are shown in more than one figure, only the first figure is listed:
- general terms are found in Figs 1–6, 8, 9, 16, 19–21, 23, 28, 29, 33, 35, 44–46, 53, 54
and 56.
- terms for the head are found in Figs 1, 3, 6–16, 18 and 22.
- the thorax in Figs 23, 24, 27–30, 32, 33 and 53.
- the wing in Figs 23 and 34–37.
- the legs in Figs 2, 38–42 and 53.
- the abdomen in Figs 43, 44 and 46–48.
- the male terminalia in Figs 54–56 and 58.
- the female terminalia in Fig. 52.

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
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Glossary of terms
Hoverfly terminology
Part
Explanation/ synonym terms
Figures
Abdomen
Abdomen
Posterior division of the body (Thompson 1999).
Figs 1A, B, 3A, C,
D, 32B, C, 43–51
acetabulum (pl.
acetabula)
Head
Rounded membranous area from which antenna protrudes; acetabula
can be separated from each other by extension of facial sclerotization
[medial sclerotized stripe (Hippa & Ståhls 2005)], which can reach
lunule; acetabula can be only partially separated or completely fused, in
this case being referred to as the antennal fossa (in narrow sense of
Sorkin & Herman 2018).
Figs 10C, D, 11A
acropod
Leg
Apical part of tarsomere 5, including arolium, empodium, unguitractor,
claws and pulvilli (McAlpine 1981).
Fig. 42A, B
acrosternum
Abdomen
Anterior sclerite on sternum II, clearly separated by a membranous area
from posterior sclerite (McAlpine 1981).
Figs 47A, B
aedeagal apodeme
(McAlpine 1981; Speight
1987)
Male
terminalia
see phallapodeme
aedeagal apodeme of
Microdontinae (Thompson
1972; Vockeroth &
Thompson 1987)
Male
terminalia
see lateral strips
aedeagal projections; apex;
ventromedial projection;
baso-ventral projection;
apico-ventral flange (see van
Steenis et al. 2016).
Male
terminalia
see ejaculatory process
aedeagus (Metcalf 1921;
Cumming & Wood 2017)
Male
terminalia
see phallus
aedeagus, stem of (van
Steenis et al. 2016)
Male
terminalia
see phallapodeme
alar callus
Thorax
Supra-alar area, slightly elevated part of the scutum just posterodorsal
from the wing base and anterior to the postalar callus, often with short
black setae (after Knight & Laffoon 1970).
Figs 28A, 29B, 30B,
32A
alula
Wing
A basal lobe along the posterior margin of the wing, located between
the calypter and anal lobe (Cumming & Wood 2017).
Figs 34B, 36D
alveolus (pl. alveoli)
General
Socket from which macrotrichia arise; sometimes the alveoli give a
granulate aspect or "granulate alveoli" to the exoskeleton, like in many
Cerioidini (McAlpine 1981).
Figs 4, 53C
anal cell (Speight 2020)
Wing
see cell cua; vein CuP
anal lobe (McAlpine 1981;
Speight 2020)
Wing
see cell a1
anal segment
Male
terminalia
see proctiger
anatergite (Cumming &
Wood 2017),
Thorax
see anatergum
anatergum
Thorax
Posterodorsal plate of the mesothoracic pleuron, posterodorsal to the
katatergum; with pile tuft in Allobaccha; part of the lateral postnota of
Speight (1987); (Thompson 1999).
Fig. 28A
anepimeron
Thorax
Plate ventral to the wing base, with three distinguishable areas in many
species: anterior, posterior and dorsomedial; anterior area always pilose,
posterior area sometimes and dorsomedial area pilose in Eristalinus
(Thompson 1999).
Figs 23C, 28B, 29A,
30

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
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anepisternum
Thorax
Anterodorsal plate of mesothoracic pleuron, consisting of a flat anterior
part and a convex posterior part in many species, although its division is
not always clear, see Nausigaster (Thompson 1999).
Figs 28, 29B, 30A
angle
General
The angle of meeting point of two lines, often used in the wing veins or
in the eye contiguity (angle of approximation), indicated by the exact
digit or the adjectives right-, acute- or obtuse-angle (Merriam et al.
2022).
Figs 5, 6C
angle of approximation
Head
In dorsal view, angle of eyes in holoptic males (Dusek & Laska 1973).
Fig. 6C
anteclypeus (McAlpine
1981)
Head
see clypeus
antecoxal piece (Shannon
1922b)
Thorax
see metasternum
antenna (pl. antennae)
Head
Sensory organ, anterodorsally placed on the head; formed by the scape,
pedicel, postpedicel and arista (Thompson 1999).
Figs 1A, 18–21
antennal fossa
Head
Fused, or partially fused, membranous acetabula (Sorkin & Herman
2018).
Figs 9D, 10A, B,
11A, C
antennal pit (Shannon 1922a)
Head
see acetabulum
antennal pits (Speight 1987)
Head
see sacculus
antennal process (Vockeroth
1971)
Head
see antennifer
antennal prominence (Curran
1925)
Head
see frontal prominence
antennal sockets (Cumming
& Wood 2017)
Head
see acetabulum
antennifer
Head
Anterodorsal extension of head, anterior to frontal prominence, on
which the antennae is placed, e.g. Cerioidini; differing from an
extended frontal prominence in that the antennifer has the lateral
margins parallel both in lateral and dorsal views (Thompson 1999).
Figs 3A, 6C, 9C,
12D
antepronotum
Thorax
Anterior part of pronotum, sclerite just above the proepisternum;
unpaired anterior sclerite of the prothorax, visible in thorax in frontal
view (Speight 1987).
Figs 23A, B, 24,B–
E, 25A, B, D, 26A–
C, 28A, 29, 30A
anterior (adv. anteriorly)
General
Towards the head end of the fly; opposite of posterior (Thompson
1999).
Figs 1B–D, 2, 38B,
42A, B, F, G, 54B
anterior anepimeron
Thorax
Anterior part of the plate ventral to the wing base, always pilose
(Thompson 1999).
Figs 29A, 30
anterior anepisternum
Thorax
The anterior, often flat, part of the anterodorsal plate of mesothoracic
pleuron (Thompson 1999).
Figs 28, 30A
anterior cervical sclerite
Thorax
Most anteriorly positioned sclerite of the cervix (Martin 1916;
Michelsen 1996).
Figs 23B, 25B, D,
26C
anterior mesanepisternum
(Speight 2020)
Thorax
see anterior anepisternum
anterior mesocoxite (Speight
1987)
Leg
see disticoxa
anterior mesonotal collar
Thorax
Transverse row of long erect pile on the anterior border of scutum, e.g.
Allobaccha, Asarkina, Hybobathus, Ocyptamus (Vockeroth 1969).
Fig. 53D
anterior ocellus
Head
Single, anteriorly placed simple eye on ocellar triangle (Thompson
1999).
Figs 6D, 12B
anterior sclerite on sternum
II (Speight 1987, Reemer &
Ståhls 2013a).
Abdomen
see acrosternum
anterior spiracle
Thorax
Respiratory opening on the anterior part of the pleuron; mesothoracic
spiracle (McAlpine 1981).
Figs 23B, 25D, 26D,
28B, 30A
anterior surstylar lobe
Male
terminalia
Anterior portion of a bilobed surstylus (Metcalf 1921).
Fig. 54A
anterior tentorial pit
Head
An invagination of the exoskeleton on the head that serves as an
internal attachment site for muscles; visible externally on the boundary
between the gena and mala (Thompson 1999).
Figs 10B, 11D, 12A,
D, 13A, B, 14A, B,
16D, 17C

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
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antero- and posterolateral
rows of stout spines
(Grković et al. 2015)
Leg
see setose carina
anterocoxal spina
Leg
Anteroventral extension of the coxa; on the metacoxa (Neocnemodon)
or on the eucoxa (Platycheirus scutatus) (after McAlpine 1981).
Fig. 42G
antetergite (Hippa & Ståhls
2005)
Abdomen
see antetergum
antetergum
Abdomen
The median sclerite at the anterior margin of tergum I (Hippa & Ståhls
2005).
Figs 43A, 44B–D,
45B, C, 46C, D
antevertex
Head
Dorsomedial part of head capsule, bordered laterally by eyes, anteriorly
by transverse frontal sulcus, posteriorly by transverse vertical sulcus,
(Lejogaster metallina). Needs further investigation, might be
homologous with vertical rugae in female Lejogaster metallina
(Harbach & Knight 1980; Sorkin & Herman 2018).
Fig. 9B
antevertical sulcus
Head
Transverse sulcus on dorsal part of head capsule bordering the
antevertex and the vertex, between the compound eyes, anterior to the
ocellar triangle; e.g. male Lejogaster metallina.
Fig. 9B
apex
General
The end of a structure, most apical point (Thompson 1999; Merriam et
al. 2022).
Fig. 2B
apical (adv. apically)
General
On, or towards, the apex of a structure; opposite to basal (Thompson
1999).
Fig. 1B
Apical section of vein A1
(Vockeroth & Thompson
1987)
Wing
see vein CuA+CuP
apically rounded anterior
process of mesotarsus
(Vockeroth 1990)
Leg
see tarsal lamina
apicoposterior lamina of
metafemur (Van Steenis et
al. 2017)
Leg
see femoral discus
apicoventral projection
(Hippa 1978a)
Leg
see tibial spina
apodemes of epiproct
Female
terminalia
Basolateral internal extensions of the epiproct; absent in some Syrphini
(Miranda & Moran 2017).
Figs 52A–C
appendage of upper process
of hypandrium (van Steenis
& Lucas 2011)
Male
terminalia
see hypandrial process
appendix
Wing
Small additional vein, arising from another vein or crossvein without
connecting to other veins (Thompson 1999); spur (Vockeroth &
Thompson 1987).
Figs 35B, C, 36B, C,
37B, C
appendix of crossvein
dm-m
Wing
Extra longitudinal vein from crossvein dm-m into cell dm, so far only
known to be present in Nephentosyrphus capitatus (Hippa 1978b).
Fig. 37D
appendix of crossvein r-
m
Wing
Additional vein from crossvein r-m into cell r4+5 found in Stilbosoma
(after Thompson 1972).
Fig. 36B
appendix of vein M1
Wing
Additional vein from vein M1 towards wing margin1 like in Eumerus,
and some Eristalinus species (Ssymank et al. 2021).
Figs 35C, 37B
appendix of vein M1+2
Wing
Additional short vein from vein M1+2 into cell r4+5; anterior appendix
R4+5. Found in Mixogaster and Aristosyrphus (after Reemer & Ståhls
2013a).
Fig. 37C
appendix of vein R2+3
Wing
Additional vein from vein R2+3 into cell r2+3, in some species of Oriental
Sphegina (Asiosphegina) (Hippa et al. 2015).
Fig. 35B
appendix of vein R4+5
Wing
Additional vein from vein R4+5 into cell r4+5; posterior appendix R4+5
(Thompson et al. 2010; Reemer & Ståhls 2013a).
Figs 35C, 36C
appressed
General
Laying, almost, flat to the body surface, most often used of recumbent
pile (Merriam et al. 2022). In Fig. 4 the scale is appressed.
Fig. 4

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
9
arcuate
General
Slightly curved, forming an arc; an adjective commonly used for
maculae or fasciae (Thompson 1999).
Figs 5, 44B, 46D
arista
Head
Macrotrichia-like structure on postpedicel, derived from modified
flagellomeres; in e.g. Psarus abdominalis and Pelecocera) incrassate; in
other species positioned apically (Stuckenberg 1999).
Figs 18A, E, 19A–C,
20, 21A, C
aristomere (pl.
aristomeres)
Head
Separate segments of the arista (McAlpine 1981).
Fig. 18B
armature
General
All kinds of expansions or projections from the exoskeleton; e.g. spina,
lamina, dens etc (Thompson 1999).
Fig. 4
arolium
Leg
Median membranous plate on tarsomere 5, bearing the empodium,
connecting the unguitractor with the empodium (McAlpine 1981).
Fig. 42A
auxiliary vein (Cumming &
Wood 2017)
Wing
see appendix of R4+5
auxillary vein in Eumerus
(Ssymank et al. 2021)
Wing
see appendix of M1
auxillary vein in
Lyneborgymyia (Ssymank et
al. 2021)
Wing
see crossvein r-m1
axillary lobe (Hull 1949)
Wing
see alula
axillary plates (Sorkin &
Herman 2018)
Wing
see axillary sclerites
axillary sclerites
Wing
Irregularly shaped plates at wing base, between the thorax and the basal
veins, the first three plates are hypothesised to be detached portions of
the base of the veins, while the fourth is supposedly mesonotal in origin
(McAlpine 1981; Dessì 2016).
Figs 23D, 29B, 30B
bacilliform sclerite (Sorkin &
Herman 2018)
Male
terminalia
see subepandrial sclerite
band (Sorkin & Herman
2018)
General
see fascia
bar (Sorkin & Herman 2018)
General
see macula
bare
General
Surface lacking vestiture, including the wing; if surface lacks
macrotrichia but with microtrichia, it should be stated as non-pilose and
not bare (narrower specification of Thompson 1999).
Figs 19A, 20B, 34B,
36A
basal (adv. basally)
General
On, or towards, the base of a structure; opposite to apical (Thompson
1999).
Figs 1B, 2B
basalare
Thorax
One of two sclerotized areas at wing base, basalare is anterior and
subalare is posterior. The basalare is often only visible as a tuberculate
part of the posterior anepisternum (Snodgrass 1935; Crampton 1942).
Fig. 30B
basale (Speight 1987)
Male
terminalia
see epandrium
base
General
Part of a structure that is attached to another more central structure of
the body; most proximal point (McAlpine 1981; Merriam et al. 2022).
Fig. 2B
basicosta
Wing
Anterobasal sclerite of wing, lateral to tegula (McAlpine 1981).
Figs 23D, 33D, 34A
basicostale (Cumming &
Wood 2017)
Wing
see basicosta
basicoxa
Leg
Dorsobasal part of the eucoxa in the mesoleg (McAlpine 1981).
Fig. 42F
basiphallus
Male
terminalia
Basal part of two-segmented phallus (Cumming & Wood 2017).
Figs 55C, D
basipulvillus (pl.
basipulvilli)
Leg
Paired connecting membrane between fifth tarsomere and pulvillis
(McAlpine 1981).
Fig. 42E
basisternum
Thorax
In frontal view of prothorax, plate between the procoxa (Crampton
1942).
Figs 23B, 25A, 26A,
C, D
basitarsomere
Leg
First/proximal tarsomere of each tarsus (after Speight 1987).
Figs 38A, B, 42B
basitarsus (Sorkin & Herman
2018; Cumming & Wood
2017)
Leg
see basitarsomere

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
10
basoflagellomere (Thompson
1999)
Head
see postpedicel
basotarsomere (Thompson
1999)
Leg
see basitarsomere
beaded (Shannon 1926b).
General
see premarginal sulcus
body length
General
Length of the fly from base of antenna to apex of abdomen (Thompson
1999).
see arrowed lines in
Fig. 1A.
bristle (Sorkin & Herman
2018)
General
see seta
buccal arm of tentorial sulcus
(Speight 1987)
Head
see subcranial sulcus
buccal cavity (HAO 2010)
Head
see subcranial cavity
bulla (pl. bullae)
General
A blister-like, round shiny swelling, found on abdominal terga in some
Afrotropical Phytomia (De Meyer et al. 2020).
Fig. 3D
calcar (pl. calcars, adj.
calcarate)
General
Elongate articulated spine-like extension of the exoskeleton, longer than
broad. In Syrphidae no articulating extensions of the exoskeleton were
found so far. The term as used in Thompson (1999) is here referred to
as spina (Sorkin & Herman 2018). Calcar is used in some calyptrate
families to refer to a more distinct postero-dorsal seta situated at the
metatibia (Cumming & Wood 2017).
not in Syrphidae
callus (Ssymank et al. 2021).
Head
see facial tubercle
callus of 1st tergite of
abdomen (van Steenis et al.
2016)
Abdomen
see lateral tubercle of tergum I
callus of sternite I (van
Steenis et al. 2016)
Thorax
see metapostnotal “protuberance”
calypter (pl. calypteres)
Wing
A membrane connecting base of wing with thoracic wall, basal to alula;
forming two lobes: dorsal calypter (dorsal lobe) and ventral calypter
(ventral lobe, thoracic squamula); the calypters fold over each other
when the wing is at rest (Thompson 1999).
Figs 23C, D, 27B,
29B, 30B, 32A, D
capitellum (Harbach &
Knight 1980)
Thorax
see capitulum
capitulum (pl. capitella)
Wing
Apical and bulbous part of the halter; knob (Sorkin & Herman 2018).
Fig. 23C
carina (pl. carinae, adj.
carinate)
General
Sharp low ridge, longer than high, found on the face, legs and genitalia
(Harris 1979; Thompson 1999).
Figs 4, 39A, D,
41B–D
cell
Wing
Any area of the wing enclosed by veins, crossveins or the wing margin,
named after the vein that forms its anterior margin, written in lowercase
(Thompson 1999).
Figs 34B, 36D
cell a1
Wing
Area of the wing posterior to vein A1; first anal cell. In the old system
anal lobe or cell a2 (McAlpine 1987; Saigusa 2006; Wootton & Ennos
1989).
Fig. 34B
cell a1; first anal cell
(McAlpine 1981)
Wing
see cell cup
cell a2; second anal cell
(McAlpine 1981)
Wing
see cell a1
cell bc
Wing
Area of the wing enclosed by vein C anteriorly, crossvein h apically,
and vein Sc posteriorly; basal-costal cell (Cumming & Wood 2017).
Fig. 34B
cell bm
Wing
Area of the wing enclosed by vein M anteriorly, M4 base and m-cu
apically, and vein CuA posteriorly; basal medial cell (Cumming &
Wood 2017).
Figs 34B, 36D
cell br
Wing
Area of the wing enclosed by vein Rs anteriorly, crossvein r-m apically,
and vein M posteriorly; basal radial cell (Cumming & Wood 2017).
Figs 34B, 36D
cell c
Wing
Area of the wing enclosed by crossvein h basally, vein C anteriorly, and
by vein Sc apically and posteriorly; costal cell (Cumming & Wood
2017).
Figs 34B, 36D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
11
cell cua
Wing
Area of the wing enclosed by vein CuA anteriorly and apically, and
vein CuP posteriorly; anterior cubital cell. Cell cup in the old system
(McAlpine 1987; Saigusa 2006; Wootton & Ennos 1989).
Figs 34B, 36D
cell cua1; first anterior
cubital cell (McAlpine 1981)
Wing
see cell m4
cell cup
Wing
Area of the wing between veins A1 and CuA+CuP; posterior cubital
cell. In the old system cell a1 (McAlpine 1981; Saigusa 2006; Wootton
& Ennos 1989).
Figs 34B, 36A
cell cup; posterior cubital
cell (McAlpine 1981)
Wing
see cell cua
cell dm
Wing
Area of the wing enclosed by M4 base basally, the anterior branch of
vein M anteriorly, crossvein dm-m apically, and vein M4 posteriorly;
discal medial cell (McAlpine 1981; Cumming & Wood 2017).
Figs 34B, 36D
cell m4
Wing
Area of the wing delimited by crossvein m-cu basally, vein M4
anteriorly, and vein CuA posteriorly; the cell is open apically; fourth
medial cell. In the old system cell cua1 (McAlpine 1981; Saigusa 2006;
Wootton & Ennos 1989).
Fig. 34B
cell r1
Wing
Area of the wing delimited by vein R1 anteriorly and vein R2+3
posteriorly; might be open or closed (when vein R1 joins R2+3 forming a
petiole) before the wing margin; first radial cell (McAlpine 1981;
Cumming & Wood 2017).
Figs 34B, 36D
cell r2+3
Wing
Area of the wing delimited by vein R2+3 anteriorly, and vein R4+5
posteriorly; second + third radial cell (McAlpine 1981; Cumming &
Wood 2017).
Fig. 34B
cell r4+5
Wing
Area of the wing enclosed by crossvein r-m basally, vein R4+5
anteriorly, vein M1 apically, and the anterior branch of vein M
posteriorly; some groups have a posteroapical appendix on the cell,
which is vein M2; fourth + fifth radial cell (McAlpine 1981; Cumming
& Wood 2017).
Figs 34B, 36D
cell sc
Wing
Area of the wing delimited by vein Sc anteriorly, and vein R1
posteriorly; in some groups might be closed apically by a crossvein sc-r;
subcostal cell (Cumming & Wood 2017).
Fig. 34B
cercus (pl. cerci)
Male
terminalia
Single-segmented pair of appendages, connected to epandrium, lateral
to anus; derived from proctiger; may be strongly developed and/or
bearing lobes e.g. Mimocalla (Cumming & Wood 2017).
Figs 48D, 51B, 54A,
55A, D, 56A, C, E,
57A, C, D
cercus (pl. cerci)
Female
terminalia
Pair of single segment structures lateral to the anus; membranous or
slightly sclerotized, position in relation to epiproct varies among taxa
(Miranda & Moran 2017).
Fig. 52
cervix
Thorax
The neck; primarily membranous area between thorax and head (Knight
& Laffoon 1970; McAlpine 1981).
Figs 23A, 26D, 30B
chaetotaxy
General
The disposition of setae/pile on the body surface, especially on the
costal vein of the wings (McAlpine 1981).
Fig. 33A
chitinous box
Male
terminalia
Usually spherical structure at the base of the phallus in Microdontinae;
Metcalf (1921) used this term to refer to the basal portion of the phallus
in general (Thompson 1969).
Fig. 56F
chitinous box sensu Metcalf
(1921)
Male
terminalia
see phallus
cicatrix (pl. cicatrices)
Leg
Sulcus or ridge-like scar on the femur and tibia of many genera within
Microdontinae (Hull 1949, see also Harris 1979).
Fig. 40A
cilium (pl. cilia)
General
Special thick pile found on the occiput in some species, e.g.,
Ceriogaster. Narrower defined than Thompson (1999).
Figs 4, 15A
claw
Leg
Paired gripping structure, apico-lateral to fifth tarsomere (Thompson
1999).
Figs 42A, E
clypeal knob
Head
Tubercle formed by postclypeus, seen in lateral view, dorsal to
subcranial cavity and ventral to facial tubercle. Not present in Pipizinae
and several Microdontinae. Adjusted from Thompson (1972) and Hippa
& Ståhls (2005).
Figs 12B, 14A, D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
12
clypeus
Head
Baso-anterior sclerite of proboscis, located between apical margin of
buccal cavity and labrum; divided into postclypeus and anteclypeus in
some Syrphidae (e.g. Syrphus); clypeus commonly used as synonym of
anteclypeus (Speight 1987).
Figs 16B, D, 17A–
C, 22
comb (Sorkin & Herman
2018)
General
see ctenidium
compound eye (Sorkin &
Herman 2018)
Head
see eye
copulatory pocket (Hippa
1986)
Female
terminalia
see genital chamber
cornea (Sorkin & Herman
2018)
Head
se facet
coronal sulcus (in part, Nayar
1964)
Head
see occipital sulcus
coronal suture (in part,
Harbach & Knight 1980)
Head
see occipital sulcus
costagium (Doczkal & Pape
2009)
Wing
see basicosta. Costagium (Séguy 1941; McAlpine 1981) is the base of
vein C, between basicosta and crossvein h. In recent Diptera manuals
this region is not differentiated from the rest of costa and thus
costagium is not a term used in Syrphidae.
coxa (pl. coxae, adj.
coxal)
Leg
First, or most basal, segment of the leg, with prefix pro- meso- or meta-
(Thompson 1999).
Figs 23A, C, 25C,
26C, 27A, C, 28A,
29A, 30A, 31, 32B,
C, 38A, C, D, 39A,
C, 40A, C, 42C, F
coxal spur (Thompson 1972)
Leg
see anterocoxal spina
cranium
Head
The sclerotized cuticle of the head, indicated in one figure only
(Snodgrass 1947).
Fig. 10A
crescent-shaped (Thompson
1999)
General
see lunulate
crossvein
Wing
A short vein connecting major longitudinal veins, referenced with
lowercase letters of the main veins it connects separated by an hyphen
(exception: crossvein h), e.g., crossvein dm-m and crossvein m-cu
(Thompson 1999).
Figs 3B, 34A, 35,
36, 37A, C, D
crossvein bm-cu; basal
medial-cubital crossvein
(McAlpine 1981)
Wing
see crossvein m-cu
crossvein bm-cu; basal
medial-cubital crossvein both
in part (McAlpine 1981)
Wing
see M4 base
crossvein c-r1
Wing
Additional crossveins between vein C and vein R1, as seen in Lycastris
(Saigusa 2006; Wootton & Ennos 1989).
Figs 3B, 35D
crossvein dm-cu; discal
medial-cubital crossvein
(McAlpine 1981)
Wing
see crossvein dm-m
crossvein dm-m
Wing
Apical crossvein between M4 and M. In the old system crossvein dm-cu
(McAlpine 1987; Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 35, 36,
37C, D
crossvein h
Wing
Short crossvein between veins C and Sc; humeral crossvein (McAlpine
1981; Cumming & Wood 2017).
Figs 34A, 35, 36A–
C
crossvein m-cu
Wing
Crossvein between veins CuA and M4; medial-cubital crossvein, bm-cu
(McAlpine 1981; Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 36A, 37C
crossvein r-m
Wing
Crossvein between veins R4+5 and anterior branch of M; radial-medial
crossvein (McAlpine 1981; Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 35A, D
crossvein r1-r2+3
Wing
Crossvein on apical part of vein R2+3 to vein R1, found in some Oriental
Sphegina (Asiosphegina) species, not always entirely reaching vein R1
(Hippa et al. 2015).
Fig. 35B

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
13
crossvein r4+5-m1
Wing
vein dividing cell r4+5 in two parts, running from vein R4+5 to vein M1,
found in the genus Lyneborgimyia (Doczkal & Pape 2009).
Fig. 37A
crossvein sc-r
Wing
Crossvein between veins Sc and R1; subcostal-radial crossvein
(McAlpine 1981; Cumming & Wood 2017); stigmal crossvein (Reemer
& Ståhls 2013a).
Figs 35A, C, 36C
ctenidial lobe (Hippa &
Ståhls 2005)
Male
terminalia
see postgonite
ctenidion, especially on the
postgonite (Hippa & Ståhls
2005)
General
see ctenidium
ctenidium (pl. ctenidia)
General
Closely set row of short spinae, comb-shaped; might be applied to a
specific structure in some male genitalia (Thompson 1999; Hippa &
Ståhls 2005).
Figs 54B, D, 56C,
58A
dens (pl. dentis, adj.
dentate)
General
A pointed, short, non-articulating extension of the exoskeleton, as long
as, or shorter than, broad (Thompson 1999).
Figs 4, 24A, 44B
dentate carina (Hippa 1978a)
Leg
see setulate carina
dichoptic
Head
Eyes do not meet each other dorsally between antennal base and vertex;
condition seen in all females and some males (Cumming & Wood
2017).
Figs 6D, 10A
discal cell; cell d (Speight
2020)
Wing
see cell dm
discal sclerite
Proboscis.
Sclerotized strengthening on the labellum, together with the epifurca,
furca and paraphysis (Schiemenz 1957).
Fig. 22
disticoxa
Leg
Apical/ventral part of the eucoxa of the mesoleg (McAlpine 1981).
Fig. 42F
distiphallus
Male
terminalia
Apical part of two-segmented phallus (Cumming & Wood 2017).
Figs 55C, D
dorsal (adv. dorsally)
General
On the upper side of a structure; opposite to ventral (Thompson 1999).
Figs 1C, D, 2, 54A,
B
dorsal occiput
Head
Most dorsal part of the occiput directly posterior to the ocellar triangle
(in part Thompson 1999), often of different texture and chaetotaxy than
rest of occiput, see further under occiput.
Figs 6A, B, 7B, 9D,
15C, 16A
dorsomedial anepimeron
Thorax
Dorso-medial part of the plate ventral to the wing base, pilose in
Eristalinus (Thompson 1999).
Fig. 29B
dorsoventral bulge (Doczkal
& Pape 2009)
Head
see postcranial tubercle
dull
General
Bodyparts or markings that are not shiny, often covered in microtrichia.
Although dull has a wider definition than matt(e), dull is the preferred
term (Merriam et al. 2022).
Fig. 3D
ejaculatory apodeme
Male
terminalia
Unpaired sclerotized structure of the sperm pump; not articulated to
other sclerites of the genitalia; its shape varies among groups
(Cumming & Wood 2017).
Figs 54C, 55C, D,
56D–F
ejaculatory duct
Male
terminalia
Tube connecting the vasa deferentia to the sperm pump; not to be
confused with the old term 'ejaculatory duct' used in Microdontinae, see
phallus (Cumming & Wood 2017).
n/a
ejaculatory hood (Metcalf
1921)
Male
terminalia
see phallus
ejaculatory process
Male
terminalia
Apically placed processes of the phallus “ejaculatory sac” in
Microdontinae (Reemer & Ståhls 2013a) and possibly also homologous
in Cerioidini (van Steenis et al. 2016).
Figs 56B, F
elongated anterior tentorial
pit (authors)
Head
see facial sulcus
emarginate (Vockeroth
1969).
General
see premarginal sulcus
emargination on
posterior eye margin
Head
Angulation of the posterior eye margin, seen from lateral view of the
head, in genera like Phytomia and Toxomerus (Thompson 1999;
Ssymank et al. 2021).
Fig. 14D
empodium
Leg
Long, seta-like, median process of the arolium (McAlpine 1981).
Figs 42A, E

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
14
endophallus
Male
terminalia
Internal seminal duct of the phallus that extends basally into the sperm
sac; only visible in some Microdontinae (Cumming & Wood 2017).
n/a
epandrial arm
Male
terminalia
Lateral extremities of the apical cleft of the epandrium (Claussen 1991);
in several Pipizella species distinctly differentiated; rarely the epandrial
arms fuse together, fully enclosing the cerci apically e.g. Victoriana
parvicornis.
Fig. 58B
epandrial rim
Male
terminalia
A border on the apical part of the epandrium in Pipizella and Ceriana
(van Steenis & Lucas 2011; van Steenis et al. 2016).
Fig. 58C
epandrium (adj.
epandrial)
Male
terminalia
Tergum IX, bearing the cerci+anus medially and the surstyli apically;
usually clefted apically, but might completely encircle the cercus+anus
(e.g. Victoriana parvicornis); articulates to the basolateral corners of the
hypandrium (Cumming & Wood 2017).
Figs 43C, 45B, 46D,
47B, 48, 49, 50, 51,
54A, 55A, C, 56C,
E, 57A, C, D, 58B, E
epaulet (Hippa 1990)
Wing
see basicosta
epifurca
Proboscis.
A small oval sclerite in the middle of the outer wall of the labellum
(Schiemenz 1957).
Fig. 22
epimeral spine of metapleura
(Reemer & Hippa 2005)
Thorax
see metapostnotal protuberance
epimeral spine of
metathoracic pleura (Speight
1987)
Thorax
see metapostnotal protuberance
epimeron (Crampton 1942)
Thorax
see proepimeron
epimeron (pl. epimera)
Thorax
Plates of mesothoracic pleuron behind posterior anepisternum;
anepimeron + katepimeron (Cumming & Wood 2017).
Figs 23C, 28, 29A,
30
epimeron of methothoracic
pleura and the metathoracic
notum sensu Speight (1987)
Thorax
see metapostnotum
epipharynx
Proboscis.
Dorsal and lateral sides of the food canal, connected with the labrum, as
part of the haustellum (Gilbert & Jervis 1998).
n/a
epiproct
Female
terminalia
Dorsal sclerite of proctiger; single plate in Microdontinae, paired
structure in other groups; it can be separate, connected by an apical
extension, or fused to cerci (Miranda & Moran 2017).
Figs 52A–C, E
episternum (Crampton 1942)
Thorax
see proepisternum
epistoma (Crampton 1942)
Head
see postclypeus
equilateral
General
All sides of the triangle of equal length and thus all angles too, often
used to indicate the relative distance of the ocelli to each other
(Merriam et al. 2022).
Fig. 5
erect
General
Standing straight up out of the body (Merriam et al. 2022). In Syrphidae
used for pile and armature, see Fig. 4 in which e.g. the pile and the
spina are erect.
Fig. 4
eucoxa
Leg
Anterior part of mesocoxa, often divided into a basicoxa and a disticoxa
(McAlpine 1981).
Fig. 42F
external process of sternite
10 (Thompson & Rotheray
1998)
Male
terminalia
see subepandrial sclerite
eye
Head
Visual organs on the postero-lateral part of the head, formed by
individual ommatidia, the compound eye (McAlpine 1981) here
shortened to eye.
Figs 8A, 12B, 15C
eye contiguity
Head
Line along which compound eyes meet in holoptic males; males of
some species eyes very narrowly separated medially leaving a bare,
shiny area free between eyes; eye-bridge sensu Doczkal & Pape (2009),
not to be confused with eye bridge of McAlpine (1981) and others,
restricted to a connection of eyes with narrow row of ommatidia
forming a bridge between the large compound eyes, not found in
Syrphidae see Merz & Haenni (2000); (Thompson 1999).
Figs 6B, 7A
eye-bridge (Doczkal & Pape
2009).
Head
see eye contiguity

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
15
face
Head
Antero-ventromedial area of head, bordered dorsally by acetabula
/antennal fossa, ventrally by mala, and laterally by eyes, or by
parafacial sulcus in several species; very variable among taxa, e.g. flat,
concave, convex, with tubercle(s), etc (Crampton 1942).
Figs 6C, 8C, D, 9C,
10A, 12A, B, D,
13A, C, 14A
facet
Head
The outer, transparent, cuticular covering of the individual ommatidia
which make up the compound eye.
n/a
facial carina
Head
Longitudinal ridge on face; not facial carina of McAlpine (1981),
Cumming & Wood (2017) and Sorkin & Herman (2018) which is a
structure separating the acetabula. The carina can either be placed
medially, in Syritta and Tropidia scita or laterally in Ceriogaster (after
Thompson 1972; Hippa & Ståhls 2005).
Figs 11B, 12A
facial depression (Sorkin &
Herman 2018)
Head
see antennal fossa
facial groove (Hippa &
Ståhls 2005)
Head
see facial sulcus
facial pit (Curran 1925)
Head
see anterior tentorial pit
facial prominence (Speight
1987)
Head
see facial tubercle
facial ridge (Doczkal & Pape
2009)
Head
see parafacia
facial stripe (Hippa & Ståhls
2005)
Head
see parafacia
facial sulcus
Head
Groove parallel to eye margin along face ending in (anterior) tentorial
pit, often a sharp border between face and paraface (Speight 1987).
Figs 10C, D, 12B,
17A, C
facial tubercle
Head
Medial to medio-ventrally positioned tubercle on the face, in Ornidia
obesa there are more "protuberances" which are called lateral facial
tubercles (Speight 1987).
Figs 7C, 10C, 11C,
D, 12B, C, 13C, D,
14, 15A, B, 17C
falcate
General
Sickle-shaped, hook-shaped (Sorkin & Herman 2018), an adjective used
in male terminalia (Hippa et al. 2015) and antennae (Reemer & Ståhls
2013a).
Fig. 5
false vein (Sorkin & Herman
2018)
Wing
see vena spuria
fascia (pl. fasciae, adj.
fasciate)
General
A transverse band (Thompson 1999).
Figs 9D, 44A, C, D,
46A, D, 53E, F
Female terminalia
Female
terminalia
The female postabdomen with genital organs and adjoining structures.
Focusing on mostly sclerotized external structures and not internal soft
tissue organs (Cumming & Wood 2017).
Fig. 52
femoral discus
Leg
Flange on the apico-posterior outline of the mesofemur in some
Eumerus species (van Steenis et al. 2017)
Fig. 39A
femoral lamina
Leg
Triangular-shaped anteroventral plate on the apex of the metafemur,
like in the genera Merodon, Tropidia and others (Ssymank et al. 2021).
Figs 38C, 40B, 41A
femoral patch of setulae
Leg
Anterobasal area on the femur with short black setulae, present only in
Eristalinae (Thompson 1999).
Fig. 39B
femoral spina
Leg
Spur on apico-lateral part of metafemur, as in genera Milesia and
Spilomyia (Hippa 1990).
Fig. 40C
femoral tubercle
Leg
Any rounded to elongate extension of femur, most often on mesofemur
as in Brachypalpus and Eumerus stackelbergi, dentate as in Syritta and
Xylota, or with setae as in Parhelophilus frutetorum (Hippa 1978a); not
triangular-shaped femoral spina or femoral lamina, see under those
terms for explanation.
Figs 39B, 41A, B
femur (pl. femora, adj.
femoral)
Leg
Third basal segment of the leg, between trochanter and tibia (Thompson
1999).
Figs 2A, 38A, D,
39A, C, 40C, D,
41A, 42G.
femoral expansion (Ssymank
et al. 2021)
Leg
see femoral lamina
fenestra, adj fenestrate
Male
terminalia
Membranous areas on genitalia; on hypandrium in several Eristalinae
but also found in other tribes (Hippa 1978a; Harris 1979).
Fig. 55C
first basal cell (Speight 2020)
Wing
see cell br

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
16
first costal cell (Speight
2020)
Wing
see cell bc
first flagellomere (Cumming
& Wood 2017),
Head
see postpedicel
first segment of flagellum
(Speight 1987)
Head
see postpedicel
flange (Sorkin & Herman
2018)
General
see lamina
foramen magnum (Sorkin &
Herman 2018)
Head
see occipital foramen
fore leg (Cumming & Wood
2017)
Leg
see proleg; both terms are interchangeable
fossette
Head
Elongate cavity on the anterodorsal surface of the postpedicel (Séguy
1961; Doczkal & Pape 2009).
Figs 18C, D
fringed plates (Hurkmans
1993)
Male
terminalia
see postgonite
fringed posteroventral
extension of subalar sclerite
(Ssymank et al. 2021)
Thorax
see plumule
frons
Head
In dorsal view, the anterodorsal part of the head, bounded anteriorly by
the lunule, laterally by the eye margin and posteriorly by the vertex, or
the eye contiguity in holoptic males (Thompson 1999).
Figs 6A, D, 7C, D,
8A, C, D, 9A–C,
13A, C
frontal
General
Used to indicate features of the frons (Sorkin & Herman 2018). This
term is thus restricted to the head and used in e.g. frontal triangle
(Thompson 1999). Not indicating any direction.
Figs 6B, C, 7A, B, D
frontal lunule (Speight 1987)
Head
see lunule
frontal prominence
Head
In lateral view the anterodorsal produced part around the antennal fossa
(parts of the face and frons), more or less triangular-shaped,
posterolaterally bounded by the eyes, and anteriorly by the lunule or the
antennifer (in part Thompson 1999).
Figs 12A, C, 13,
14A, B, D, 15A
frontal rugae
Head
Area of rugae on ventral part of frons; Phytomia (De Meyer et al. 2020)
Fig. 11D
frontal striae (Speight 2020)
General
see regulae
frontal triangle
Head
In holoptic males, the frons is bordered posteriorly by the eye
contiguity, giving it a triangular shape (Thompson 1999).
Figs 6B, C, 7A, B
frontal tubercle
Head
Tubercle on frons, dorsal to frontal prominence, found in some species
of Nausigaster. Not frontal tubercle of Speight (1987) which is frontal
prominence and not frontal tubercle of McAlpine (1981) which is a
structure of the vertex, hypothesised to be modified ocelli.
Fig. 15B
frontal tubercle (McAlpine
1981)
Head
a structure of the vertex, possibly modified ocelli
frontal tubercle (Speight
1987)
Head
see antennifer
fumose, fumeus (Sorkin &
Herman 2018)
General
see infuscate
fulcrum
Proboscis.
Extension sclerite of the rostrum (Gilbert & Jervis 1998)
Fig. 22
furca
Proboscis.
Sclerotized strengthening on the labellum, together with the epifurca,
apical sclerite and paraphysis (Schiemenz 1957).
Fig. 22
furcasternum
Thorax
Furcasternum, a distinct part of the sternum, serving as a site for muscle
attachment (McAlpine 1981).
Figs 25A, 26C
furcate
General
Latin for forked (Sorkin & Herman 2018), used in the postpedicel
which can be bi- or multifurcate in Cacoceria and several
Microdontinae, also used for pile or features of the terminalia.
Figs 21B, D
gena (pl. genae)
Head
Area on head ventral to eye, anterior to occiput and posterior to tentorial
pit and buccal sulcus; more restricted definition (as Snodgrass 1960),
not broader definition used by McAlpine (1981) and Thompson (1999),
which includes part of mala, after Crampton (1942).
Figs 11C, D, 12,
13B–D, 14, 15A,
16B, D, 17B–D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
17
gena of authors (McAlpine
1981; Thompson 1999)
Head
see parafacia
genal sulcus
Head
Groove on the ventral part of the head, extending from the anterior
tentorial pit to the eye margin (after Speight 1987).
Figs 12A, 13A, 16B,
17A
genal suture (Doczkal &
Pape 2009)
Head
see genal sulcus
genital chamber
Female
terminalia
Membranous pocket, invaginated into segment VIII, with external
opening between apex of sternum VIII and hypoproct; may have a
distinct sternum IX on its dorsal wall; a more restricted view of the term
genital chamber of Kotrba (2000), which is here limited to the external
invaginated area located between the secondary gonopore and the
genital opening (Miranda & Moran 2017).
Figs 52D, E
genital opening
Female
terminalia
Opening of genital chamber to exterior; ventrally located, between
sternum VIII and hypoproct (Kotrba 2000; Miranda & Moran 2017).
Figs 52D, E
genital opening (Cumming &
Wood 2017)
Female
terminalia
see secondary gonopore
genital orifice/genital cleft
(Kotrba 2000)
Female
terminalia
see genital opening
gonite (Claussen 1991)
Male
terminalia
see postgonite
Gonotreme (Nayar 1965),
gonotrema (Kotrba 2000)
Female
terminalia
see genital opening
granulum (pl. granula,
adj. granulate)
General
Upheaved ornamentation of cuticle, grain-like, triangular to rounded
and often black found in Cerioidini and some Paragus species. In
Syrphidae, granula always surrounding single pilus or alveoli (Sorkin &
Herman 2018).
Fig. 53C
hair (Speight 1987)
General
see pile
haltere (pl. halteres)
Wing
Drumstick-shaped reduced second wing, for balance during flight;
consists of scabellum, pedicellum and capitulum (Thompson 1999).
Figs 23C, D, 27C,
29A
hamus (pl. hami)
Male
terminalia
Hook-like paired structure attached dorso-basally to the phallus and to
the interior dorso-lateral wall of the hypandrium, and seamlessly
connected ventrally to the apex of the phallapodeme. Seen in Eumerus;
possibly homologous to the 'lateral sclerite of the aedeagus' in Merodon
(Doczkal 1996).
Fig. 54D
hang-vein (Speight 2020)
Wing
see appendix R4+5
Head
Head
Anterior division of the insect body (Thompson 1999).
Figs 1A–C, 3A, 5–
17, 53C
hind leg (Cumming & Wood
2017)
Leg
see metaleg; both terms are interchangeable
haustellum
Proboscis.
Apical of the two main parts of the proboscis (Gilbert & Jervis 1998).
Fig. 22
holoptic
Head
Eyes meet each other dorsally between antennal base and vertex;
condition seen only in males (Cumming & Wood 2017).
Figs 6B, C, 10B
horn-shaped production
(Curran 1941)
Abdomen
see lateral tubercle of tergum II
humeral plate (Speight 1987;
Cumming & Wood 2017)
Wing
see basicosta
humerus, humeral callus
(McAlpine 1982)
Thorax
see postpronotum
hyaline
General
Transparent or clear; mostly used for the wing (Thompson 1999).
Fig. 35D
hypandrial arms
Male
terminalia
Apico-dorsal portion of hypandrium that articulates with base of
subepandrial sclerite, usually connecting dorsally over phallus
(Cumming & Wood 2017). Usually fused in Syrphidae, forming dorsal
wall on hypandrium, and can be narrow/short to wide/long;
subepandrial sclerite always articulating with basal portion of this area.
Fig. 55D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
18
hypandrial labium
Male
terminalia
Weakly chitinous flange on the baso-dorsal margin of the hypandrium,
found in several species of Pipizella; inner median flange of
hypandrium; "auffaltung der dorsalen Hypandriumwand" (Claussen
1991; van Steenis & Lucas 2011).
Fig. 58B
hypandrial process
Male
terminalia
Additional extension of the hypandrium, most often tooth-like and
apically placed; upper process of hypandrium; appendage upper process
of hypandrium (van Steenis & Lucas 2011).
Figs 58D, E.
hypandrium (adj.
hypandrial)
Male
terminalia
Sternum IX + fused gonocoxites (indistinguishable from one another),
ventral segment of male genitalia, articulating to baso-lateral corners of
epandrium; bears postgonites apically; seem to have two distinct
components in Microdontinae: a basal, convex in lateral view,
sclerotized part and an apical, microtrichose, less sclerotized part,
possibly fused gonocoxal component (Reemer & Ståhls 2013a).
Figs 43C, 46D, 47B,
48A–C, 49A, 50A,
51A, C, D, 54B, D,
55B, D, 56A, C, E,
57A, C, D, 58D, E.
hypopharynx
Proboscis.
Tongue-like process between the labrum and the rest of the haustellum;
with salivary canals (Gilbert & Jervis 1998).
Fig. 22
hypopleuron (McAlpine
1981)
Thorax
see meron
hypoproct
Male
terminalia
Sclerite ventral to cerci, ventral to anus; indistinguishable in male
Syrphidae; not to be confused with the subepandrial sclerite (Cumming
& Wood 2017).
n/a
hypoproct
Female
terminalia
Membranous unpigmented to lightly pigmented; as a distinct plate only
in the Microdontinae; might bear a posterior apodeme (Miranda &
Moran 2017).
Figs 52D, E
hypopygium
Male
terminalia
Epandrium, hypandrium and associated structures (Cumming & Wood
2017).
Figs 55C, 57A, C, D
hypostomal bridge
Head
Region ventral to occipital foramen, bounded by the postgena, and
sometimes separated by a suture, including transverse crest of
hypostomal bridge (Doczkal & Pape 2009); not hypostomal bridge of
Doczkal & Dziock (2004), which is the postgena (McAlpine 1981).
Figs 15C, D, 16A, C
incrassate
General
Thickened, swollen; often used in combination with the shape of the
metafemur or the arista (Sorkin & Herman 2018).
Figs 19C, 20D, 41A
inferior lobe of gonite
(Claussen & Hayat 1997)
Male
terminalia
see ventral postgonite
infuscate (adj.
infuscated)
General
Darkened; an adjective used for a partly to entirely darkened wing
(Sorkin & Herman 2018).
Figs 35B, 36A
inner median flange of
hypandrium; auffaltung der
dorsalen Hypandriumwand
(Claussen 1991; van Steenis
& Lucas 2011)
Male
terminalia
see hypandrial labium
inner prong of the
ejaculatory hood (Thompson
1974
Male
terminalia
see inner surstylar lobe
inner surstylar lobe
Male
terminalia
Basal lobe on medial surface of surstylus in Trichopsomyia and several
Sphegina; "zahn des syrstylus" (Claussen et al. 1994; Hippa et al.
2015).
Fig. 58F
isosceles
General
A triangle with two sides of equal length, often used to indicate the
relative distance of the ocelli to each other (Merriam et al. 2022)
Fig. 5
katatergite (McAlpine 1981)
Thorax
see katatergum
katatergum
Thorax
Dorsoposterior plate of mesothoracic pleuron, dorsal to posterior
spiracle (Thompson 1999).
Figs 28A, 30A
katepimeron
Thorax
Posteroventral plate of the mesothoracic pleuron; demarcation between
katepimeron and meron often weak (Thompson 1999).
Figs 23C, 28, 30A
katepisternum
Thorax
Anteroventral plate of mesothoracic pleuron; sternopleuron of older
authors (Thompson 1999).
Figs 28, 29B, 30A,
31
knob (Cumming & Wood
2017)
Wing
see capitulum

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19
labellum
Proboscis.
Apical cushion-like prolongation of the labium, with pseudotracheae;
they are highly modified labial palps (Gilbert & Jervis 1998).
Fig. 22
labium
Proboscis.
Forms the ventral wall of the proboscis, the prementum + labellum;
connected to apical part of fulcrum (Gilbert & Jervis 1998)
n/a
labrum
Proboscis.
Dorsal and lateral sides of the food canal, connected with the
epipharynx, as part of the haustellum (Gilbert & Jervis 1998).
Fig. 22
lacinia
Proboscis.
Blade-like sclerite, connected with the maxillary palp and stipes
(Gilbert & Jervis 1998))
Fig. 22
lamina (pl. laminae, adj.
laminate)
General
Thin extension of the exoskeleton, not much longer than high, plate
(Thompson 1999).
Figs 4, 38B, C, 40B,
41A
lateral (adv. laterally)
General
At the side, away from the centre; opposite of medial (Thompson 1999).
Fig. 1B
lateral arm of lunule
Head
The lunule consists of two lateral arms and in many cases a medial arm
(Speight & Sarthou 2017).
Figs 10C, D
lateral cervical sclerite
Thorax
Laterally positioned sclerite of the cervix (Martin 1916).
Figs 23B, 25A, C,
D, 26C
lateral facial strips (Shannon
1922a)
Head
see parafacia
lateral facial tubercles
Head
Tubercles on the dorso- and ventrolateral side of face as in Ornidia
obesa (Thompson 1972).
Fig. 14C
lateral keel (Thompson 1972)
Head
see facial carina
lateral lobes to epiproct
Female
terminalia
Small pigmented area located baso-laterally to the epiproct in
'Eristalinae'; might bear pile; assumed as tergum IX by authors
(Miranda & Moran 2017).
Fig. 52C
Lateral parapsidial suture
(Cumming & Wood 2017)
Thorax
see parapsidal suture
lateral plate (Thompson
1972)
Leg
see femoral lamina
lateral sclerite of phallus
Male
terminalia
Sclerotized structure that sheathes the phallus in Merodon; seemingly
continuous with the phallapodeme (Marcos-García et al. 2007).
Fig. 54C
lateral strips
Male
terminalia
In some Microdontinae, basal dark lines on both sides of the ejaculatory
hood that seem to extend into the hypandrium (Reemer & Ståhls 2013a,
b).
Fig. 56E
lateral tubercle of
tergum I
Abdomen
Rounded and slightly upheaved section on anterolateral corner of
tergum I in several Microdontinae and Cerioidini; erroneously
mentioned as callus on 2nd tergite in Speight (1987).
Figs 3A, 29B, 43A,
46A, 53F
lateral tubercle of
tergum II
Abdomen
Dens-like protuberance on anterolateral margin of tergum II, in
Nausigaster (Shannon 1922a) and Ubristes (Reemer & Ståhls 2013a).
Fig. 47E
laterotergite (McAlpine
1981)
Thorax
see anatergum and katatergum
laterotergite (Speight 1987)
Thorax
see anatergum
laterotergum
Thorax
Lateral part of postnotum ventrally from the scutellum, the anatergum +
katatergum (McAlpine 1981).
Fig. 27C
Leg
Leg
The thoracic locomotory organ; paired organs in descriptions used in
singular form, e.g. proleg, mesoleg and metaleg; proleg (singular) in
contrast to prolegs, which is the term used for the locomotory organs of
dipteran larvae (Thompson 1999).
Figs 1A, B, D, 2,
32B, C, 38–42, 53A,
B
lingula
Male
terminalia
An apical projection from the ventral surface of the hypandrium, e.g.
Merodon tarsatus (Metcalf 1921; Speight 1987).
Figs 56A, C, 58A
lingular appendages; apico-
lateral; medio-dorsal
projection; medio-ventral
flange; dorso-basal tooth (see
van Steenis et al. 2016).
Male
terminalia
see lingular process
lingular process
Male
terminalia
Apically placed processes of lingula, e.g., Cerioidini (van Steenis et al.
2016).
Figs 56C, 58A
longitudinal depression
(Sedman 1964)
Head
see medial frontal sulcus

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
20
longitudinal furrow (Sedman
1964)
Head
see medial frontal sulcus
lower pair (Shatalkin 1981)
Female
terminalia
see apodemes of the epiproct
lunulate
General
Adjective for more deeply curved macula or vitta (Thompson 1999).
Figs 5, 44C
lunule
Head
Anterior boundary of frons, above acetabula; different texture and
usually shiny, bare and differently coloured than rest of frons,
consisting of two lateral arms and in many cases a medial arm; not
lunule of Cumming & Wood (2017) (Thompson 1999).
Figs 6A, B, D, 7C,
D, 8D, 9B, 10A, B,
11A, C
M4 base
Wing
Base of vein M4, a crossvein between veins M4, M and crossvein m-cu;
crossvein bm-m in Cumming & Wood (2017). In the old system
crossvein m-cu and bm-cu, in part (McAlpine 1981).
Figs 34A, 37C
macrotrichium (pl.
macrotrichia, adj.
macrotrichose)
General
Vestiture connected to nerves and arising from an alveolus. Found on
the body surface and sometimes also on the wing veins, comprising
pile, cilium, seta, setula and scale (Thompson 1999).
Figs 4, 39A, B
macula (pl. maculae, adj.
maculate)
General
A marking on the insect body, requiring an adjective to describe its
shape, e.g. arcuate, lunulate, rectangular (= bar), punctate, triangular,
round (= spot) (Thompson 1999).
Figs 3D, 9D, 43D,
44A–C, 45A, C,
46C, D
mala (pl. malae)
Head
Anteroventral part of face (Taxo-Fly); not a true structure but area often
non-pilose and black with shiny areas, contrasting to rest of face; part of
prefrons (Crampton 1942), part of the rostrum or nasus in Tipulidae
(Cumming & Wood 2017) and part of the "snout" in Syrphidae
(Ssymank et al. 2021).
Figs 12A, C, D, 13,
14A, C, D, 15B,
16D, 17C, D
malar tubercle
Head
Lateral protuberance at the antero-ventral corners of the anteroventral
part of the face, i.e. mala.
Figs 11B, 12B, 13B,
14B
Male terminalia
Male
terminalia
The male postabdomen with its genitalia and adjoining structures
(Cumming & Wood 2017)
Figs 43C, 46A, D,
47B, C, 48–51, 54–
57
marginal cell; cell M
(Speight 2020)
Wing
see cell r1
markings
General
Different patterns of the integument of the body, might be from
different colouration/reflection of the exoskeleton or different
coloured/type of microtrichia/macrotrichia; further classified into
macula, fascia or vitta (Thompson 1999).
Figs 3D, 9D, 43D,
44A–C, 45C, 46C, D
matt(e) (Merriam et al. 2022)
General
see dull
maxillary palp
Proboscis.
Sensory appendage on the maxilla (Speight 1987).
Fig. 22
medial (adv. medially)
General
On, or towards, the middle/centre of a structure (Thompson 1999).
Fig. 1B
medial arm of lunule
Head
The lunule consists of two lateral arms and in many cases a medial arm
(adopted from Speight & Sarthou 2017).
Fig. 10D
medial callus, in Graptomyza
(Ssymank et al. 2021)
Head
see facial tubercle
medial frontal sulcus
Head
Medial longitudinal impression on the frons; in some species visible as
a non-pruinose shiny depression (after Sedman 1964, 1965).
Figs 6B, D, 11C
medial surstylar lobe
Male
terminalia
Medial lobe of the surstylus on the ventral margin (Hippa 1978a).
Fig. 54A
median keel (Thompson
1972)
Head
see facial carina
median mesocoxite (Speight
1987)
Leg
see basicoxa
median postnotal sclerite of
mesonotum (Speight 1987)
Thorax
see mediotergum
median spinose ridge (Hippa
1978a)
Leg
see tibial carina
median vein (Speight 2020)
Wing
see vein M

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21
median-cubital crossvein;
crossvein m-cu (Speight
2020)
Wing
see crossvein dm-m
mediocoxal spina
Leg
Medio-lateral extension on the mesocoxa (McAlpine 1981).
Fig. 42F
mediotergal suture
Thorax
Dorsoventral suture on the posterior part of the thorax, lateroventrally to
the scutellum, located between the medio- and laterotergum
Fig. 27B
mediotergum
Thorax
Part of the postnotum ventral to the scutellum; part of subscutellum
sensu Doczkal & Dziock (2004) (Cumming & Wood 2017). In some
Cyclorrhapha, named the dorsal transverse convex bulge bordering the
mediotergum as subscutellum (McAlpine 1981).
Figs 27B, C
membranous socket
(McAlpine 1981)
General
see alveolus
meron
Thorax
Posteroventral plate of the mesothoracic pleuron ventrally to
katepimeron, The demarcation between the meron and the katepimeron
is not always clear, earlier authors used meropleuron for this fused
plates; meropleuron, hypopleuron (McAlpine 1981).
Figs 23C, 28A, 29B,
32B, 42F, G.
meropleuron (McAlpine
1981)
Thorax
see meron
meso
General
Related to the mesothorax; middle, mid; used for the leg or thoracic
pleura (Thompson 1999).
Fig. 2A
mesoanepimeron (Thompson
1999)
Thorax
see anepimeron
mesoanepisternum
(Thompson 1999)
Thorax
see anepisternum
mesocoxite of middle leg
(Speight 1987)
Leg
see eucoxa
mesoleg
Leg
The leg, related to the mesothorax (Thompson 1999).
Fig. 2A
mesonotum
Thorax
Dorsal part of thorax including scutum and scutellum (Thompson
1999).
Fig. 23A
mesopleuron (Thompson
1999)
Thorax
see anepisternum
mesoscutum (Thompson
1999)
Thorax
see mesonotum
mesothoracic leg (Sorkin &
Herman 2018)
Leg
see mesoleg
meta
General
Related to the metathorax; last, hind; used for the leg or thoracic pleurae
(Thompson 1999).
Fig. 2A
metabasisterno-precoxite
(Speight 1987)
Thorax
see metasternum
metaepimeron, in part
(Thompson 1999)
Thorax
see metepimeron
metakatepimeron
Thorax
Sclerite of the metepimeron, anterodorsally to metacoxa. The different
sclerites of the metepisternum are not always clearly defined, visible in
some Microdontinae (Tachi 2014).
Figs 32B, C
metakatepisternum
Thorax
Sclerite of the metepisternum, antero-dorsally to metacoxa. The
different sclerites of the metepisternum are not always clearly defined
(Tachi 2014).
Figs 23C, 28B, 29,
32B, C
metaleg
Leg
The leg, related to the metathorax (Thompson 1999).
Fig. 2A
metanepimeron
Thorax
Sclerite of the metepmeron, antero-dorsally to metacoxa. The different
sclerites of the metepisternum are not always clearly defined (Tachi
2014).
Figs 32B, C
metanepisternum
Thorax
Sclerite on which the posterior thoracic spiracle is embedded in. Part of
the metepisternum, not always clearly defined (Tachi 2014).
Figs 28B, 32B, C
metanotum
Thorax
Sclerite of the metathorax, ventrally to the postnotum and hidden under
the connection of tergum I and the thorax, so only visible when
detaching the abdomen from the thorax (Crampton 1942).
Figs 27A, B

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
22
metanotum sensu Hippa &
Ståhls (2005).
Thorax
see subscutellum
metapleuron
Thorax
Sclerite ventrally to the metanotum. The metapleuron is differentiated
into the presutural metepisternum (EPS) and postsutural metepimeron
(EPM) by the metapleural suture (Tachi 2014).
Figs 32D, E
metapostnotal
"protuberance"
Thorax
Tuberculate or dens-like protuberance on the dorsolateral margin of the
metapostnotum, in dorsal view visible at the anterolateral corner of
tergum I, clearly visible in Neoascia and several Cerioidini (after Tachi
2014). Epimeral spine of metathoracic pleura (Speight 1987) or
epimeral spine of metapleura (Reemer & Hippa 2005).
Figs 27D, 30A, 45A,
46A, B
metapostnotal tubercle
Thorax
Tubercle on posteromedial surface of metapostnotum, might be
functioning as articulating point with tergum I (see Tachi 2014).
Fig. 29B
metapostnotum
Thorax
Connective sclerotized membrane between abdomen and thorax, visible
as two round projections at anterolateral corner of tergum I, sometimes
connected dorsally along "metanotum" and lateroventrally ending in the
metepimeron (Tachi 2014). In part metepimeron sensu Thompson
(1999).
Figs 23C, 27A, C,
D, 28, 29A, 30A,
32B, C, 43A–C,
44A, D, 45A, 46C
metasternum
Thorax
Ventral thoracic plate anterior to metacoxa; metabasisterno-precoxite
(Speight 1987) is a more accurate term, but not likely to be used, nor
used in the past (Shannon 1926a; Thompson 1999).
Figs 28A, 29B, 31
metathoracic leg (Sorkin &
Herman 2018)
Leg
see metaleg
metathoracic spiracular pile
patch (Thompson 1972)
Thorax
see posterior spiracular fringe
metepimeron
Thorax
A small sclerite ventrally between the metepisternum sensu McAlpine
(1981) and metapostnotum (Tachi 2014).
Figs 28B, 29B, 32D,
E
metepisternum
Thorax
Anterior part of metathoracic pleuron; combined sclerite of
metakatepisternum (ventral part) and metanepisternum (dorsal part)
together (Tachi 2014).
Fig. 32D
microtrichium (pl.
microtrichia, adj.
microtrichose)
General
Usually smaller vestiture, without an alveolus or nerve connection,
found on the entire body surface and especially used in connection to
the wing (Thompson 1999).
Figs 4, 34B
mid coxal prong (McAlpine
1981)
Leg
see mediocoxal spina
mid leg (Cumming & Wood
2017)
Leg
see mesoleg; both terms are interchangeable
mouth opening (HAO 2010)
Head
see subcranial cavity
neck (Cumming & Wood
2017)
Thorax
see cervix
notal wing lamina
Thorax
Flap-like extension of the scutum at the base of the wing, e.g. found in
Eumerus, Nausigaster (Thompson 1999; Hippa & Ståhls 2005).
Fig. 28A
notal wing process
Wing
Lateral processes of scutum which articulate with axillary sclerites of
wing; 1. anterior notal wing process connects to medioposterior axillary
sclerite (first axillary sclerite); 2. median notal wing process (pleural
wing process), connects to medioanterior axillary sclerite (second
axillary sclerite); 3. posterior notal wing process, connects to
lateroanterior axillary sclerite (third axillary sclerite), and the apical
portion of this process is assumed to have been detached from the
thoracic wall and represents the fourth axillary sclerite. The processes
are inconspicuous due to their articulation with the axillary wing
sclerites (McAlpine 1981; Dessì 2016).
n/a
notal wing shield (Thompson
1972)
Thorax
see notal wing lamina
notaulus (Sorkin & Herman
2018)
Thorax
see parapsidal suture
notched; oral margin
(Thompson 1972; Hippa &
Ståhls 2005)
Head
see clypeal tubercle

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
23
notopleural sulcus
Thorax
Sulcus anterior to notopleuron and ending medially in transverse sulcus.
Same term in Coleoptera (Evans 1974) and Hemiptera (Ouvrard et al.
2002), but homology uncertain, this term is here used for the first time
in Syrphidae.
Fig. 29A
notopleural suture (Crampton
1942)
Thorax
see parapsidal suture
notopleuron
Thorax
Anterolateral part of the scutum posterior to postpronotum and anterior
to transverse sulcus; presutural area, -callus, -depression (Thompson
1999).
Figs 23A, D, 24,
30A, 53F
oblique
General
An adjective to denote the direction of e.g. macula (Thompson 1999).
Figs 5, 44B, 45C
occipital carina
Head
Ridge-like part on the posterodorsal part of the postcranium, or the
posterior margin of the dorsal occiput in many species of the genera
Ceriana and Eumerus, after Doczkal & Pape (2009). Thickened part of
the occiput posterior to the ocellar triangle (Thompson 1972).
Figs 3A, 6C, 7A,
9C, 12D, 15D
occipital foramen (pl.
occipital foramina)
Head
Contiguous opening in the postcranium, with two finger-like projections
making the opening have a figure 8 appearance. Bounded ventrally by
the hypostomal bridge (Nayar 1964; Harbach & Knight 1980).
Figs 15D, 16C
occipital setae (Sorkin &
Herman 2018)
General
see cilium
occipital sulcus
Head
Dorsal sulcus on the postocciput, lateroventral border of the postvertex;
not occipital sulcus sensu Sorkin & Herman (2018), after Speight
(1987).
Figs 15C, 16A
occipital tubercle
Head
Rounded swelling on the dorsoposterior margin of the postocular orbit;
as seen in Spheginobaccha (Thompson 1999)
Fig. 8A
occiput
Head
Posterior area of head closest to posterior eye margin, consisting of a
dorsal (or lateral, area immediately posterior of the ocellar triangle),
medial (posterior of the eye margin) and ventral (posteroventrally to eye
margin) part; differentiated from postocciput by presence of
macrotrichia and, in some species, separation by postcranial carina; a
broader definition than Cumming & Wood (2017) (Thompson 1999).
Figs 6A, C, 7A, B,
D, 8B, C, 12B, C,
13B, 14A, 15C, D,
16A, C
ocellar triangle
Head
Triangular elevated area on which the three ocelli are situated
(Thompson 1999).
Figs 6A, C, 7A, B,
D, 8A–C, 9B, C,
10A, B, 13A, B, D,
15B, C
ocellus (pl. ocelli)
Head
Simple eye (single beadlike lens), located medially on vertex/vertical
triangle, one anterior and two posterior (Thompson 1999), in some
Microdontinae only two or even four present (Reemer & Ståhls 2013a).
Figs 6D, 12B
ocular arm of anterior
tentorial sulcus (Speight
1987)
Head
see genal sulcus
ocular strips (Vujić &
Claussen 2000)
Head
see paravertica
odd little lobes (Hull 1949)
Abdomen
see ventral dens of tergum IV
ommatidium (pl.
ommatidia)
Head
Single unit of the compound eye (McAlpine 1981).
n/a
oral fossa (HAO 2010)
Head
see subcranial cavity
orbital strips (Speight 1987)
Head
see parafacia
orientation
General
In the three dimensional world there are three planes, in insects they are
the sagittal, the transverse and the horizontal plane. The orientation of
body parts in each of the planes is given by the following terms: lateral-
medial; dorsal-ventral and anterior-posterior. An additional fourth
orientation indicating an in- or outwards direction has the terms apical-
basal (Thompson 1999).
Figs 1B–D, 2
oval
General
Oval shaped, an adjective used to indicate the shape of the
basoflagellomere, the abdomen or macula (Sorkin & Herman 2018).
Figs 5, 44A

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
24
parafacia (pl. parafaciae,
adj. parafacial)
Head
A narrow strip on the frontal part of the face located posterior to the
buccal, facial, and/or genal sulcus, anterior to the eyes, and dorsal to the
gena; not parafacial of McAlpine (1981), since that is defined by the
facial ridge and ptilinal suture, which are limited to Schizophora (after
Thompson 1999).
Figs 10D, 11B, C,
12A–C, 13B, C,
14A, 16B, 17A, B,
D
paraphysis
Proboscis
Sclerotized strengthening on the labellum, together with the epifurca,
furca and discal sclerite (Schiemenz 1957).
Fig. 22
parameral sheath (Cumming
& Wood 2017)
Male
terminalia
see phallus
parameral sheet
Male
terminalia
Fused and modified parameres; combined with the aedeagus to form the
phallus (Cumming & Wood 2017).
n/a
paramere (McAlpine 1981)
Male
terminalia
see postgonite
paraphysis
Proboscis.
Sclerotized strengthening on the labellum, together with the epifurca,
furca and discal sclerite (Schiemenz 1957).
Fig. 22
parapsidal suture
Thorax
Line of junction between the scutum and pleuron; suture along the
scutum ventrally to the notopleuron and anteriorly to the notal wing
lamina (McAlpine 1981).
Fig. 29B
parasagittal sulcus (Speight
1987)
Head
see occipital sulcus
paravertica (pl.
paraverticae)
Head
Lateral longitudinal area on vertex, along eye margin; delimits a strip
along eye margin of different texture than rest of frons, see parafacia
(ocular strips Vujić & Claussen 2000). Not the region where the
paravertical bristles are located (Steyskal 1976).
Figs 8B, 9A
paravertical sulcus
Head
Sulcus on the dorsal part of the head along the eye-margin separating
the paravertica from the rest of the vertex.
Fig. 9A
pectinate
General
Comb-shaped; very densely arranged setae on either side of the
structure where it is found; one type of arrangement for the vestiture of
the arista (Sorkin & Herman 2018).
Fig. 21A
pedicel
Head
Second antennal segment, between the scape and postpedicel
(Stuckenberg 1999).
Figs 18A, B, 19D,
20B
pedicellum
Wing
Medial part of halter, the stem; connecting the scabellum (base) to the
capitulum (knob) (Harbach & Knight 1980).
Fig. 23C
penis sheath (Metcalf 1921)
Male
terminalia
see hypandrium
peristoma
Head
Sharp narrow part at lower region of the mala in some species of
Sphegina (e.g. S. latifrons, S. licina), separating the gena and the rest of
the mala from the subcranial cavity along the ventrolateral part of the
head; not epistoma, as that is regarded to be the postclypeal region
(Crampton 1942) after van Steenis et al. (2018b).
Fig. 13A
petiole (adj. petiolate)
General
A stem or stalk on a structure, narrower than the rest of the structure;
commonly used to refer to the base (petiole) or overall shape (petiolate)
of the abdomen or wing cells (Thompson 1999).
Fig. 46B
phallapodeme
Male
terminalia
Rod-shaped appendage articulating with the base of the phallus,
supporting its movement during copulation; might have apical
modifications which associate through different lengths with the
phallus; absent in Microdontinae, except African Spheginobaccha
(Reemer & Ståhls 2013a; Cumming & Wood 2017).
Figs 54C, D, 55B–
D, 56B, D, 57
phallotrema
Male
terminalia
External genital opening at the apex of the phallus (Cumming & Wood
2017).
n/a
phallus
Male
terminalia
Intromittent copulatory organ, aedeagus + parameral sheath; might be a
single or two-segmented (basiphallus and distiphallus) structure. In
Microdontinae divided into ejaculatory hood and ejaculatory duct
(Thompson 1969): ejaculatory hood involves and follows most of the
shape of internal space where sperm is pumped through, with a basal
spherical part (chitinous box) and tubular part that bifurcates into dorsal
and ventral processes (Metcalf 1921; Thompson 1969).
Figs 48A, 49B, 50B,
54C, D, 55B, 56B,
D, E, 57, 58B, D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
25
pile; (sing. pilus); (adj.
pilose); (pl. pili)
General
A threadlike macrotrichium covering the body of adult insects; thinner
than setae/setulae; Latin noun for hair; use of pile is recommended for
pragmatic reasons, leaving singular 'pilus' for specific cases where the
user needs to refer to a single one (Shannon 1922a, in part Thompson
1999).
Figs 4, 19B, 20C
plate (Sorkin & Herman
2018)
General
see lamina
pleural suture
Thorax
Vertical suture line from the mesocoxa to the anterior wing base,
between anepisternum and anepimeron often forming a membranous
cleft between these sclerites (Crampton 1942; McAlpine 1981).
Figs 28A, 30B
pleuron (pl. pleura)
Thorax
Lateral part of thorax (Sorkin & Herman 2018).
Figs 28–30
pleurotergite (Thompson
1999)
Thorax
see katatergum
plumose
General
Most often used to refer to an arista with distinct vestiture, in this case
long pile on the entire surface of the arista (Sorkin & Herman 2018).
Figs 20A, 21C
plumule
Thorax
Extended posteroventral margin of the subalar sclerite, dorsal to the
anepimeron, pilose; often feather-like (Thompson 1999).
Figs 23C, 27B, 30B
pollen, pollinose (Thompson
1999)
General
see pruinescence
post-anal hood
Male
terminalia
Membranous lobe placed between the two surstyli, connected to the
subepandrial sclerite; postanal hood; postanalanhang; postanallamelle
(Claussen 1991; Claussen et al. 1994; Coovert & Coovert 1996).
Figs 58C, E, F
post cephalic region (Speight
1987)
Head
see postcranium
postocular orbit (Speight
1987)
Head
see occiput
postabdomen
Female
terminalia
Usually telescoped into the preabdomen; usually less sclerotized or with
different patterns of sclerotization when compared to the preabdominal
segments; segment VII and onwards for most Syrphinae, VI and
onwards for the remaining groups (Miranda & Moran 2017).
Fig. 52
postalar callus
Thorax
Posterolateral elevated part of the scutum (Thompson 1999).
Figs 23A, D, 24,
28B, 30A, 32A, D
postalar carina
Thorax
Ridge running from postpronotum to wing base (after McAlpine 1981).
Figs 32A, D
postalar pile tuft (Thompson
1999)
Thorax
see supra-alar pile tuft
postalar ridge (McAlpine
1981).
Thorax
see postalar carina
postalar wall
Thorax
Ventrolateral surface below the postalar carina, often with a different
texture than the postalar carina (McAlpine 1981).
Fig. 32A
postalare, postalar bridge
(Sorkin & Herman 2018).
Thorax
see postalar carina
postclypeus
Head
Dorsal or basal part of a divided clypeus; normally if the proboscis is
retracted into the buccal cavity, the postclypeus is actually placed
anteriorly to the clypeus (Speight 1987).
Figs 16B, 17A, 22
postcranial carina (Speight
1987)
Head
see postcranial suture
postcranial suture
Head
Border between occiput and postocciput, seen as an angulate structure
on the head capsule (adjusted from Speight 1987).
Fig. 16B
postcranial tubercle
Head
Elevated part lateral to the occipital foramen; same area of the "band of
sensilla on postgena" sensu Speight (1987); often not present but might
be differentiated by the "band of sensilla" or another different texture
(adjusted from Doczkal & Pape 2009).
Figs 8A, 15C, D,
16A, C
postcranium
Head
Posterior portion of the head, posterior to the compound eyes,
consisting of the occiput, postgena, postocciput and hypostomal bridge
(McAlpine 1981).
Fig. 16A
posterior (adv.
posteriorly)
General
Away from the head end of the fly; opposite of anterior (Thompson
1999).
Figs 1B–D, 2, 54B

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
26
posterior anepimeron
Thorax
Posterior part of the plate ventral to the wing base, pilose in some
species (Thompson 1999).
Figs 29A, 30B
posterior anepisternum
Thorax
Posterior convex part of the anterodorsal plate of mesothoracic pleuron
(Thompson 1999).
Figs 28, 30A
posterior cell; cell po
(Speight 2020)
Wing
see cell r4+5
posterior cervical sclerite
Thorax
Posteroventrally positioned sclerite of the cervix, mostly triangular
shaped sclerite (Martin 1916).
Figs 23B, 25A, C,
26C
posterior mesocoxite
(Speight 1987)
Thorax
see meron
posterior ocellus (pl.
ocelli)
Head
Two simple eyes, symmetrically placed on the posterior part of the
ocellar triangle (Thompson 1999).
Figs 6D, 12B
posterior spiracle
Thorax
Metathoracic spiracle (McAlpine 1981).
Figs 27B, D, 29B
posterior surstylar lobe
Male
terminalia
Posterior portion of a bilobed surstylus (Metcalf 1921).
Fig. 54A
posterior tentorial pit
Head
Invagination of the exoskeleton on the head that serves as an internal
attachment site for muscles; visible externally on the posterior part of
the head, ventrolaterally to the occipital foramen (Harbach & Knight
1980).
Figs 15C, D, 16C
posterior tentorial sulcus
Head
Sulcus on the postocciput from the hypostomal bridge to the posterior
tentorial pit (Nayar 1964).
Figs 15D, 17B
postero-lateral spina of
abdomen
Abdomen
Sharp posterolateral triangular extension on terga III and IV, as seen in
several Chrysotoxum species (Shannon 1926b).
Fig. 44B
postgena
Head
Ventral part of postcranium. Harbach & Knight (1980), McAlpine
(1981).
Figs 15C, D, 16,
17B, D
postgonite (pl.
postgonites)
Male
terminalia
Pair of articulated lobes on apical portion of the hypandrium, flanking
the phallus; hypothesised to be derived from the gonocoxite; might be
fused to hypandrium or absent, e.g. Microdontinae (Sinclair 2000).
Figs 55B, D, 56A,
C, 57A, C, D, 58A,
B, D, E.
postmetacoxal bridge
Thorax
Sclerotized area posterior and dorsal to the metacoxa connecting the
epimeron with the furcasternum. Tending to be correlated with petiolate
abdomen and enlarged metafemora (Thompson 1999).
Fig. 30A
postnotum
Thorax
Thoracic sclerite bounded by the scutellum and the metanotum divided
into a medial part and two lateral parts the mediotergum and
laterotergum (Crampton 1942).
Fig. 27A
postoccipital suture (in part,
Harbach & Knight 1980),
Head
see postcranial suture
postocciput
Head
Posterior part of head, occiput of many authors, here differentiated from
occiput as more posteroventral area and separated from occiput by
postcranial suture. In some species divided into dorsal and ventral parts
by medially elevated area (Harbach & Knight 1980; McAlpine 1981).
Figs 15C, 16A, C
postpedicel
Head
Third segment of the antenna where the arista is inserted, used in
Brachycera (Stuckenberg 1999).
Figs 18A, D, 19D,
20A, B
postpronotum
Thorax
The elevated area on anterolateral part of the scutum; humerus or
humeral callus; pronotum, the dorsal part of the most anterior part of the
scutum, which is greatly reduced in Diptera, where the remaining
elevated part is called postpronotum (Thompson 1999).
Figs 23A, B, 24,
25A, B, 26B, 28A,
29A, 30A, 53E.
postscutellum (Cumming &
Wood 2017)
Thorax
see subscutellum
postvertex
Head
Slightly elevated area posteroventrally from postocular orbit, ending
ventrally in the occipital sulcus (Speight 1987); part of the median
occipital sclerite sensu McAlpine (1981).
Figs 15C, 16C
premarginal sulcus
General
Groove or furrow along the margin of a sclerite, usually found on the
scutellum or abdomen (Thompson 1999).
Figs 44A, B
prementum
Proboscis.
Ventral plate of the labium; premental sclerite of labium (Speight
1987).
Fig. 22
premetacoxal bridge sensu
Doczkal & Pape (2009).
Thorax
see metasternum

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
27
premetacoxite (Speight
1987)
Thorax
see metasternum
presutural area, -callus, -
depression (Crampton 1942)
Thorax
see notopleuron
primary gonopore
Female
terminalia
Internal; opening from the common oviduct into the anterior part of the
vagina, anterior to the openings of the spermathecal ducts and accessory
glands (Kotrba & Weniger 2017).
n/a
pro
General
Related to the prothorax; first or fore; used for the leg or thoracic pleura
(Thompson 1999).
Fig. 2A
Proboscis
Proboscis.
Mouthparts of flies which are adapted for sucking (Gilbert 1981).
Figs 16B, 22
Process, pl. processes
General
A prominent or projecting part of an organism or organic structure
(Merriam et al. 2022).
Figs 56B, C, F, 58A,
D, E
procoxal bridge
Thorax
see proepisternum
proctiger
Male
terminalia
All structures posterior to segment IX; in male Syrphidae restricted to
anus + cerci (Cumming & Wood 2017).
n/a
proctiger
Female
terminalia
Epiproct + hypoproct + anus + cerci (Miranda & Moran 2017).
n/a
produced posteroventral
margin of subalare
(McAlpine 1981)
Thorax
see plumule
proepimeron
Thorax
Sclerite lateral to procoxa, ventral of anterior spiracle (Speight 1987).
Figs 25B, 28A, 29B,
30A
proepisternum
Thorax
Sclerite dorsal to procoxa, anteroventrally to anterior spiracle; procoxal
bridge (Speight 1987).
Figs 23B, 25B, D,
26B, 29A
projecting postero-lateral
angles (Vockeroth 1992)
Abdomen
see posterolateral spina of abdomen
proleg
Leg
The leg related to the prothorax (Thompson 1999), not to be confused
with prolegs, the locomotory organs in Syrphidae larvae.
Fig. 2A
pronotum (Thompson 1999)
Thorax
see postpronotum
prosternum (Knight &
Laffoon 1970)
Thorax
see basisternum
prothoracic basisternum
(Speight 1987)
Thorax
see basisternum
prothoracic leg (Sorkin &
Herman 2018)
Leg
see proleg
pruinosity (adj.
pruinose)
General
Microtrichia resembling a cover of fine powder/dust on any body area
except the wing (Harris 1979; Cumming & Wood 2017). Pruinosity is
here used as a synonym of pruinescence.
Figs 45C, 46D, 53E,
F
pseudo-mystax
Head
Aggregation of strong pile situated on postclypeus, in some species of
Mallota and Nausigaster; comparable to the feature found in the family
Asilidae (McAlpine 1981).
Fig. 15B
pseudovein
Wing
Vein-like thickening of the membrane posterior to vein CuP, but
without an enclosed trachea. In the old system vein CuP (McAlpine
1981; Wootton & Ennos 1989; Saigusa 2006).
Fig. 34A
pteropleuron (Thompson
1999)
Thorax
see anepimeron
pterostigma
Wing
Pigmented area on the apex of cell sc; supports gliding and reduces
vibration (Cumming & Wood 2017).
Fig. 34B
pubescence (Thompson
1999)
General
see pruinosity
pulvillus (pl. pulvilli)
Leg
Pair of lobes located on the base of the claws on the fifth tarsomere
which aids the fly in holding on to the surface (Thompson 1999).
Figs 42A, E
punctum (pl. puncta,
adj. punctate)
General
Minute pit depressions on exoskeleton, spot-like (Harris 1979;
Thompson 1999).
Figs 3A, 4
pyxis of the aedeagus
(Speight 1987)
Male
terminalia
see phallus

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
28
R5 (Curran 1923)
Wing
see appendix crossvein r-m
radial sector vein Rs1+2
(Speight 2020)
Wing
see vein R2+3
radial sector vein Rs3+4 + M1
(Speight 2020)
Wing
see vein R4+5+M1
radial vein, vein R (Speight
2020)
Wing
see vein Rs
rectangular
General
A shape with right angles but sides of different length, an adjective used
to denote the shape of macula (Merriam et al. 2022).
Figs 5, 44A, 46C
regula (pl regulae, adj.
regulose)
General
Linear furrows and upheavals on the exoskeleton, visible as closely set
sulci and carinae, especially on the head in genera such as Chrysogaster
and Orthonevra (Speight 1987).
Fig. 6A
remigium (see McAlpine
1981)
Wing
see stem vein
respiratory spiracle
General
see spiracle
ridge (McAlpine 1981)
General
see carina
rostrum
Proboscis.
Basal of the two main parts of the proboscis (Gilbert & Jervis 1998).
Fig. 22
ruga (pl. rugae, adj.
rugose)
General
Small rounded, depressed spots on the exoskeleton, as seen on the face
or frons of several taxa, e.g. Ceriana, Phytomia and Melanogaster
(Harris 1979; Sorkin & Herman 2018).
Figs 8D, 9C, 11D,
12D
sacculus (pl. sacculi)
Head
All kinds of excavations on the lateral part of the postpedicel, in
contrast to the anterodorsally placed fossette (McAlpine 2011).
Figs 18A, D, E,
19A–C, 20B, 21A, C
scabellum
Wing
Basal part of the haltere, rich in sensilla (Harbach & Knight 1980).
Fig. 23C
scale
General
Flattened pilus, more reflective than other surrounding pili; present on
the ventral surface of the occiput in different genera or on other parts of
the body of Lepidomyia and Myolepta (Thompson 1999).
Fig. 4
scape
Head
First antennal segment, articulating on the head capsule (Stuckenberg
1999).
Figs 18A, B, 19D,
20B
sclerite
General
Any plate of the body wall bounded by a membrane or sutures (Sorkin
& Herman 2018)
n/a
scutellar dens
Thorax
Paired tooth like protuberance on the posterior margin of the scutellum
e.g. in Microdon (Thompson 1999)
Fig. 24,A
scutellar depression
Thorax
Apicomedial depression on the scutellum as seen in e.g. Brachyopa
bicolor. In Copestylum and Graptomyza often with a different texture
than the rest of the scutellum (see Ssymank et al. 2021).
Fig. 33B
scutellar fringe
Thorax
Pile fringe along the posteroventral part of the scutellum (Vockeroth
1969).
Figs 27A, B, 33C
scutellum
Thorax
The dorsoposterior semicircular part of the thorax, or posterior sclerite
of the scutum (Thompson 1999).
Figs 23A, D, 24,
27A, 28A, 30A, 32A
scutoscutellar sulcus
Thorax
Groove between scutum and scutellum, it is possibly not a true
connecting line between the scutum and the scutellum so the term
suture (McAlpine 1981) does not seem to be correct in this case (after
McAlpine 1981).
Figs 23A, 32A
scutum
Thorax
Main sclerite (anterior) of the mesonotum, in dorsal view between the
scutellum and the head (Thompson 1999).
Figs 23A, D, 26A,
27A, 32A, D
second basal cell (Speight
2020)
Wing
see cell bm
second costal cell (Speight
2020)
Wing
see cell c
secondary gonopore
Female
terminalia
External opening of the vagina into the genital chamber (Kotrba 2000).
n/a
secondary gonopore (male)
(Cumming & Wood 2017)
Male
terminalia
see phallotrema
secondary sclerite
Thorax
Sclerite lateral to the prothoracic basisternum (Speight 1987).
Figs 23B, 25C, 26A

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
29
sella
Thorax
Sclerite of the cervical region, bearing sensilla, visible in frontal view of
prothorax between lateral cervical sclerite and basisternum; sella of
cervical organ (Speight 1987).
Figs 23B, 25A, D
sensory pit (Sorkin &
Herman 2018)
Head
see sacculus
seratostylate (Crampton
1942)
Head
see apical arista
seta (pl. setae, adj.
setose)
General
Large macrotrichium much longer than wide; thicker than pilus, longer
than setula; difference between seta and setulae is arbitrary since it
depends on the surrounding vestiture (Thompson 1999).
Figs 4, 39B, 41B
setose carina of
metafemur
Leg
On the apicoventral margin of the metafemur there are one or two
carinae, either anterior, medial or posterior or combination of anterior
and posterior, with short to long setae in several genera; e.g.
Chalcosyrphus, Eumerus and Xylota (Hippa 1978a).
Figs 39A, D, 41B, C
setula (pl. setulae, adj.
setulate)
General
Macrotrichium, slightly longer than wide; thicker than pilus, shorter
than seta; difference between setae and setulae is arbitrary since it
depends on the surrounding vestiture (Thompson 1999).
Figs 4, 399B
setulate carina of
metatibia
Leg
Basoventral carina with setulae; e.g. Xylota (Hippa 1978a).
Figs 39B, D
sharp edge at the ventral
apex of tibia 3 (Doczkal &
Dziock 2004)
Leg
see tibial carina, apico-ventral
shining (of many authors)
General
see shiny
shiny
General
Used for a surface of the body which glistens, or that reflects light as if
polished; that shines; not synonymous to 'shining' which means to emit
light like the sun, a lamp or fireflies; might be combined with 'metallic'
when it is similar to the reflecting metals (Merriam et al. 2022).
Fig. 3D
size
General
Length of body (parts), usually given to tenth of millimetre; wing length
is usually measured from the basicosta to apex; body length from base
of antenna to apex of abdomen (Thompson 1999).
see arrowed lines in
Fig. 1A
sperm duct
Male
terminalia
Membranous tube connecting the sperm pump to the phallus:
ejaculatory duct (Cumming & Wood 2017).
n/a
sperm pump
Male
terminalia
The combined sperm sac + ejaculatory apodeme responsible for
pumping sperm through the phallus (Cumming & Wood 2017)
n/a
sperm sac
Male
terminalia
Membranous sperm reservoir (Cumming & Wood 2017).
n/a
spermatheca (pl.
spermathecae)
Female
terminalia
Internal sclerotized structures responsible for storing male sperm
(Miranda & Moran 2017).
n/a
spina (pl. spinae, adj.
spinose)
General
Elongate, non-articulating extension of the exoskeleton, much longer
than broad. Different from a calcar as it is non-articulating and hence
calcar is not found in Syrphidae. All previous spurs or calcaris are now
named spina (in part Thompson 1999).
Figs 4, 38B–D, 39D,
40C, 42F, G
spine (Snodgrass 1935;
McAlpine 1981)
General
see spina
spinose ridge, apicoventral
lateral or apicoventral
median spinose ridge (Hippa
1978a).
Leg
see setose carina
spiracle
General
Respiratory opening, two on either side of the thorax and on the lateral
membranous surface of each abdominal sternum (Thompson 1999).
Figs 23B, 26D, 27D,
28B, 29B, 32B, C,
48B, D, 49D, 51D
spiracle (pl spiracles)
Abdomen
Respiratory opening; embedded in the lateral membranous part of the
sternum (McAlpine 1981).
Figs 29B, 48B, D,
49D, 51D
spiracular fringe
Thorax
Row or patch of long pile anteroventral to the posterior spiracle, e.g.
Psilota, Rhingia and Eristalodes (Thompson 1999).
Fig. 33D
spot (Sorkin & Herman
2018)
General
see macula

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
30
spur (Snodgrass 1935; Sorkin
& Herman 2018)
General
see calcar; so far not found in Syrphidae
spur, as used in the veins
(Vockeroth & Thompson
1987)
Wing
see appendix
spurious vein (Cumming &
Wood 2017)
Wing
see vena spuria
squama, squamula (Linnaeus
1758; Cumming & Wood
2017)
Wing
see calypter
squarish
General
A shape with equal sides at right angles, an adjective used to denote the
shape of macula (Merriam et al. 2022).
Figs 5, 44C
stem vein
Wing
Thickened base of vein R between wing base and vein M (Cumming &
Wood 2017).
Fig. 34A
sternite (Cumming & Wood
2017; McAlpine 1981)
General
see sternum
sternite (McAlpine 1981;
Cumming & Wood 2017;)
Abdomen
see sternum
sternopleuron (Shannon
1922a)
Thorax
see katepisternum
sternum (pl. sterna)
General
Ventral division of any segment of the thorax or Abdomen The
sclerotized part should actually be called sternite (McAlpine 1981), but
as the abdominal sterna in several species consist of a sclerotized and a
membranous parts, here the term sternum can be used as a synonym of
sternite and the term "membranous part of sternum" refers to the non-
sclerotized part (Snodgrass 1935; Thompson 1999).
Figs 28B, 29A, 30,
43C, 47A–C, E,
48A, B, D, 49, 50B,
51
sternum (pl. sterna)
Abdomen
Ventral division of any segment of the abdomen; used here for the
sclerotized ventral division of each segment of the abdomen, coded with
Roman numbers I–IX (Snodgrass 1935, Thompson 1999).
Figs 28B, 29A, 30,
32B, C, 43C, 47A–
C, E, 48A, B, D, 49,
50B, 51
Sternum 10 (Cumming &
Wood 2017)
Female
terminalia
see hypoproct
sternum VII
Female
terminalia
Present as a lightly pigmented area to a distinct sclerotized plate; shape
can vary among taxa (Miranda & Moran 2017).
Figs 52D, E
sternum VIII
Female
terminalia
Present as a lightly pigmented area to a distinct sclerotized plate; shape
can vary among taxa (Miranda & Moran 2017).
Figs 52D, E
sternum IX
Female
terminalia
May be completely membranous or as a hardened sclerotized plate on
the dorsal surface of the genital chamber; the wholly membranous
sternum IX are easily everted during preparation of specimens; the
opening visible on this structure is the secondary gonopore (Miranda &
Moran 2017).
Figs 52D, E
sternum, membranous
part
Abdomen
Ventral division of any segment of the abdomen; used here for the
membranous ventrolateral division of each segment of the abdomen
(Snodgrass 1935).
Fig. 48B
stigma of wing (Speight
2020)
Wing
see pterostigma
stipes
Proboscis.
Basal sclerite of the maxilla, bearing the lacinia and maxillary palp
(Sorkin & Herman 2018).
Fig. 22
stripe (Sorkin & Herman
2018)
General
see vitta
style (Thompson 1999)
Head
see apical arista
styli (Speight 1987)
Male
terminalia
see surstylus
subalare
Thorax
One of two sclerotized areas at wing base, subalare is posterior and
basalare is anterior. Posteriorly often bearing the plumule (Snodgrass
1935; Crampton 1942).
Figs 29B, 30A

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
31
sub-anal plate (Kotrba 2000)
Female
terminalia
see hypoproct
sub-epaulet (Thompson
1999)
Wing
see basicosta
subapical prolateral dentate
plate-like projection (Hippa
1978a)
Leg
see femoral lamina
subapical prolateral ventral
spur (Hippa 1990)
Leg
see femoral spina
subcranial cavity
Head
Ventral cavity of the head where the proboscis can be retracted into
(McAlpine 1981).
Figs 10B, 16B, D,
17B
subcranial margin (in part,
Speight 1987)
Head
see peristoma
subcranial sulcus
Head
A short groove on the ventral part of the face from the anterior tentorial
pit to the buccal cavity; may be complete, incomplete or absent (after
Speight 1987).
Figs 11D, 12B, C,
13C, 16B, 17A
subepandrial membrane
Male
terminalia
Membranous roof of the pouch that separates the epandrium and
proctiger from the hypandrium and postgonites (Cumming & Wood
2017)
n/a
subepandrial sclerite
Male
terminalia
Sclerite formed on the subepandrial membrane, located internally in the
genitalia, between epandrium and hypandrium; articulates apically with
the base of the surstyli or apex of the epandrium, and basally with the
anterodorsal surface of the phallus or the hypandrial arms (Cumming &
Wood 2017).
Figs 55A, D, 56A,
57A, D, 58E.
subgena (McAlpine 1981)
Head
see peristoma
submarginal cell; cell sm
(Speight 2020)
Wing
see cell r2+3
subscutellum
Thorax
Ventral to the scutellum, and supposed to be the dorsal part of the
mediotergum (part of the postnotum) (McAlpine 1981; Cumming &
Wood 2017); postscutellum (Cumming & Wood 2017)
Figs 27A, B
sulcus (pl. sulci, adj.
sulcate)
General
Invagination of the exoskeleton seen as distinct furrows on the outside
of the insect body; not to be mistaken with suture (Snodgrass 1960).
Figs 6B, D, 10C, D,
11C, 12A–C, 13A,
15B, C, 16A, B,
17A–C, D, 44A, B
superior lobe of gonite
(Claussen & Hayat 1997)
Male
terminalia
see postgonite
superior/inferior lobe
(Metcalf 1921; Speight 1987;
Thompson 1999)
Male
terminalia
see postgonite
supra-alar area
Thorax
The lateral margin of the scutum immediately dorsally to the attachment
of the wing (McAlpine 1981).
Figs 32A, D
supra-alar pile tuft
Thorax
A dense congregation of pile on the lateral side of the scutum, anterior
to the postalar callus and posterior to the wing base found in
Eristalinus, close to the postalar carina (after Thompson 1999).
Fig. 32D
supra-anal plate (Speight
1987; Kotrba 2000)
Female
terminalia
see epiproct
surstylar apodeme, sternum
X, minis (Speight 1987)
Male
terminalia
see subepandrial sclerite
surstylus (pl. surstyli,
adj. surstylar)
Male
terminalia
Paired clasping structure, articulated externally on the apex of the
epandrium and internally on the apex of the subepandrial sclerite; might
be highly modified with extensions and lobes (Speight 1987).
Figs 45B, 46D, 47B,
C, 48, 49A, B, 50,
51, 54A, 55A, D,
56A, C, E, 57A, C,
D, 58C
sustentacular apodeme
(Metcalf 1921)
Male
terminalia
see phallapodeme

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
32
suture
General
Lines/divisions seen on the body where different sclerites meet
(Snodgrass 1960).
Figs 16B, 27B, 28A,
29B, 30B
tarsal cavum
Leg
Excavation of the tarsus; alternatively, the tarsus with this condition can
be called a cavate tarsus or a tarsus cavatum (Sorkin & Herman 2018).
Fig. 42D
tarsal lamina
Leg
Ventrally curved part on the posterior surface of tarsomeres 1-4 on the
mesotarsus as seen in Pyrophaena granditarsa (Vockeroth 1990).
Fig. 42B, 53A
tarsomere (pl.
tarsomeres)
Leg
Individual segment of tarsus, five in total; most basal is basitarsomere,
next are 2nd, 3rd, 4th and most apical is 5th tarsomere (Thompson 1999).
Figs 42A, B, D, E.
tarsus (pl. tarsi, adj.
tarsal)
Leg
Fifth and apical segment of the leg, consisting of 5 tarsomeres and the
acropod (Thompson 1999).
Figs 2, 38A, 40D,
41D
tegula
Wing
Sclerite at base of wing, lateral to basicosta; often (Fig. 32D) with dense
tuft of setae (Thompson 1999). Tegula in e.g. Eristalinus divided into
two parts, large and proximal "basi-tegula"; small and apical "disti-
tegula".
Figs 23D, 32D
temporal sulcus
Head
A sulcus on the postcranium dorsolaterally from the occipital foramen
(Nayar 1964).
Figs 15C, D, 16A
temporal tubercle
Head
A structure on the posterior part of the head, dorsal to the occipital
foramen, often absent or only denoted by a weak swelling or different
texture on the post occiput; area where the supracervical setae
(Cumming & Wood 2017) are located.
Fig. 15D
tentorial sulcus (Speight
1987)
Head
see facial sulcus
terga 9+10 (Cumming &
Wood 2017)
Female
terminalia
see epiproct
tergite (Cumming & Wood
2017; McAlpine 1981)
General
see tergum
tergite (McAlpine 1981;
Cumming & Wood 2017)
Abdomen
see tergum
Tergite 9 (Hippa 1986;
Speight 1987; Jilong &
Zhihua 1992)
Female
terminalia
see lateral lobes to the epiproct
tergum (pl. terga)
General
The dorsal division of any segment of the thorax or Abdomen Tergite
(McAlpine 1981) is used for the sclerotized part and tergum for the
entire part. In Syrphidae the entire dorsal surface of each sclerite is
entirely sclerotized (Thompson 1999), so here we use tergum as
synonym of tergite.
Figs 29, 30A, 43,
44D, 45A, B, D,
46A, C, 47D, E,
48A, C, D, 49, 50,
51
tergum (pl. terga)
Abdomen
Dorsal division of the abdomen; used here for the sclerotized dorsal
division of each segment of the abdomen, coded with Roman numerals
I-X (Thompson 1999).
Figs 29, 30A, 32B,
C, 43, 44D, 45A, B,
D, 46A, C, 47D, E,
48A, C, D, 49, 50,
51
tergum 10 (Hippa 1986)
Female
terminalia
see epiproct
tergum IX
Female
terminalia
Kotrba (2000) considers tergum IX as absent in most Cyclorrhapha (or
fused to X, i.e., epiproct/supra-anal plate) (Kotrba 2000; Miranda &
Moran 2017).
n/a
tergum VII
Female
terminalia
Present as a lightly pigmented area to a distinct sclerotized plate; shape
can vary among taxa (Miranda & Moran 2017).
Fig. 52
tergum VIII
Female
terminalia
Present as a lightly pigmented area to a distinct sclerotized plate; shape
can vary among taxa (Miranda & Moran 2017).
Fig. 52
tergum VIII of Speight
(1987)
Abdomen
see sternum VIII
theca (Speight 1987)
Male
terminalia
see hypandrium
Thorax
Thorax
Second division of the insect body, between the head and abdomen
(Thompson 1999).
Figs 1A, 3C, 23–31

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
33
tibia (pl. tibiae, adj.
tibial)
Leg
Fourth segment of the leg, located between the femur and tarsus
(Thompson 1999).
Figs 2, 38A, B, 39A,
40B, D, 42D
tibial carina
Leg
Ridge along the basoventral line of the metatibia, well visible as a
darkened ridge and often with black or yellow setulae in Xylota (Hippa
1978a).
Fig. 41D
tibial carina, apico-
ventral
Leg
Ridge-like edge on the apico-ventral margin of the metatibia in several
species of Brachyopa (after Doczkal & Dziock 2004).
Fig. 53B
tibial cavum
Leg
Excavation of the tibia; alternatively, the tibia with this condition can be
called a cavate tibia or a tibia cavatum (Sorkin & Herman 2018).
Fig. 41D
tibial lamina
Leg
Ventro-apical extension of the metatibia, sometimes there is both an
anterior and posterior extension; present in several genera like
Brachypalpus, Chalcosyrphus and Merodon. Sometimes this extension
is more flange-like and thus called tibial lamina (Hippa 1978a).
Fig 38B
tibial spina
Leg
Ventro-apical extension of the metatibia, sometimes there is both an
anterior and posterior extension; present in several genera like
Brachypalpus, Chalcosyrphus and Merodon. Sometimes this extension
is more flange-like and should be called tibial lamina (Hippa 1978a).
Figs 38B, C
tibial tubercle
Leg
Any rounded or more or less elongate extension of the tibia, like in
Brachypalpus chrysites (Hippa 1978a).
Fig. 40A
tomentum (adj.
tomentose)
General
Thick vestiture; usually refers to the condition of the thick pile that is
densely arranged and forms areas completely covering the exoskeleton,
in genera such as Meromacrus and Quichuana (Thompson 1999).
Fig. 3C
tooth (Sorkin & Herman
2018)
General
see dens
transparent (Speight 1987)
General
see hyaline
transverse frontal sulcus
Head
A transverse groove along the posterior border of the frons between the
frons and the (ante)vertex, connecting the two compound eyes, only
found in dichoptic specimens (Raffray 1897; Gumovsky 2001).
Figs 7D, 8, 9B, C
transverse sulcus
Thorax
Anterolateral groove separating notopleuron from the posterior part of
the scutum, can be complete or incomplete (Speight 1987).
Figs 23A, 24, 28,
29A, 30B, 32A, D
transverse sulcus (Speight
1987)
Head
see temporal sulcus
transverse suture (Thompson
1999)
Thorax
see transverse sulcus
triangular
General
A shape with three sides, an adjective used for macula (Merriam-
Webster 2022).
Figs 5, 45A, 46D
triangular processus of
metafemur (Hurkmans 1993)
Leg
see femoral lamina
trochanter (pl.
trochanters, adj.
trochanteral)
Leg
Second segment of the leg, located between the coxa and femur
(Thompson 1999).
Figs 31, 38A, D,
40A–C, 42C, F, G
trochanteral dens
Leg
Short triangular extension, often on the metatrochanter, in genera like
Eumerus, Merodon and Xylota (Hippa 1978a).
Fig. 38C
trochanteral pile tuft
Leg
Lateral pile tuft on protrochanter like in Platycheirus scutatus; cluster
of rather long stiff setae (Vockeroth 1990).
Fig. 42C
trochanteral process of
posterior mesocoxite of
mesoleg (Speight 1987)
Leg
see mediocoxal spina
trochanteral spina
Leg
Long thin extension, often on the postero-ventral side, of the
mesotrochanter, like in Neocnemodon and Xylotini (Hippa 1978a).
Figs 38D, 39D
tubercle (pl. tubercles,
adj. tuberculate)
General
Rounded to oval protuberance on the body, e.g. facial, abdominal and
clypeal tubercle (Thompson 1999).
Figs 3A, 38A, 41A,
B
tubercle (Thompson 1999)
Head
see facial tubercle
tubus of the aedeagus
(Speight 1987)
Male
terminalia
see phallus
unguis (McAlpine 1981)
Leg
see claw

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
34
unguitractor
Leg
Medial connecting plate between fifth tarsomere, claws and empodium
(McAlpine 1981).
Fig. 42E
upper gonocercus; dorsal
gonocercus (Verlinden 1999;
van Steenis et al. 2018a)
Male
terminalia
see postgonite
upper process of hypandrium
(van Steenis & Lucas 2011)
Male
terminalia
see hypandrial process
vagina
Female
terminalia
Internal organ situated on the ventral part of segment VIII; constituted
of different internal pouches and where the common oviduct,
spermathecal ducts and accessory glands open into (Kotrba 2000;
Kotrba & Weniger 2017).
n/a
vasa deferentia
Male
terminalia
Sperm ducts (Merriam et al. 2022).
n/a
Vein
Wing
Longitudinal sclerotized structure for stabilising the wing membrane
(Sorkin & Herman 2018).
Figs 34A, 35, 36, 37
vein A1
Wing
Anterior vein. Vein A2 in the old system (McAlpine 1981; Saigusa
2006; Wootton & Ennos 1989)
Figs 34A, 35A, C,
D, 36B, C
vein A1; first anal vein
(McAlpine 1981)
Wing
see vein CuP
vein C
Wing
Anterior thickened margin of the wing; costal vein (McAlpine 1981;
Cumming & Wood 2017).
Figs 33D, 34A, 35,
36A–C
vein CuA
Wing
Cubital vein; anterior branch of cubitis. Vein CuA2 in the old system
(McAlpine 1981; Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 35A, C,
D, 36A–C
vein CuA1; first anterior
cubitus vein (Mcalpine 1981;
Speight 2020)
Wing
see vein M4
vein CuA2; second anterior
cubitus vein (McAlpine
1981; Speight 2020)
Wing
see vein CuA
vein CuA+CuP
Wing
Posteroapical appendix of cell cua. Apical section of A1 (Vockeroth &
Thompson 1987). Vein A1 + CuA2 in the old system (McAlpine 1981;
Saigusa 2006; Cumming & Wood 2017).
Figs 34A, 36A
vein CuP
Wing
Cubital vein; posterior branch of cubitis. Vein A1 in the old system
(McAlpine 1981; Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 35B, 36A,
D
vein CuP; posterior cubital
vein (McAlpine 1981)
Wing
see pseudovein
vein M
Wing
Middle vein, between veins R and CuA; medial vein (McAlpine 1981;
Saigusa 2006; Wootton & Ennos 1989).
Fig. 34A
vein M1
Wing
Branch of M that joins R4+5, in some groups joining as close to the wing
margin; its apical end might be directed to wing apex (processive) or
towards base (recessive), or M1 might be wholly straight (Cumming &
Wood 2017).
Figs 34A, 35, 36B,
37A, B, D
vein M1+2
Wing
Apical part of vein M from M4 base to the point where M1 branches off
and where in some species vein M2 starts (Cumming & Wood 2017)
Figs 34A, 37D
vein M2
Wing
A short stump at the point where M1 branches off from vein M1+2
(Cumming & Wood 2017).
Figs 34A, 35C, 36A,
C, 37A–C
vein M4
Wing
Fourth median vein, vein CuA1 in the old system. This vein sometimes
extends beyond crossvein dm-m as a postero-apical appendix of cell dm
(Saigusa 2006; Wootton & Ennos 1989).
Figs 34A, 37D
vein MA
Wing
Anterior branch of medial vein (Saigusa 2006; Wootton & Ennos 1989).
Fig. 34A
vein R
Wing
Main vein of the wing; branches into R1 and Rs, and the latter branches
into R2+3 and R4+5; radius, radial vein (Cumming & Wood 2017).
Figs 34A, 36A
vein R1
Wing
Anterior branch of vein R (Cumming & Wood 2017).
Figs 34A, 35A, C,
36
vein R1+R2+3
Wing
Petiole of cell r1 to vein C, closing cell r1 (after Hippa & Ståhls 2005);
cell r1 closed; cell r2+3 closed (Vockeroth & Thompson 1987); cell r1
closed and petiolate by Thompson et al. (2010).
Fig. 36D

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
35
vein R2+3
Wing
Anterior branch of vein Rs (Cumming & Wood 2017).
Figs 34A, 35, 36
vein R4+5
Wing
Posterior branch of vein Rs; might bear a short branch (auxiliary vein,
appendix) into cell r4+5 (Cumming & Wood 2017). Deeply looped into
cell r4+5 in some groups (Fig. 36D).
Figs 34A, 35A, C,
36B, C, 37A
vein R4+5+M1
Wing
Petiole of cell r4+5 to vein C (Hippa & Ståhls 2005) cell R4+5 closed;
R3+4+M1 (sensu Speight 1987); last section of R4+5 (Vockeroth &
Thompson 1987).
Figs 34A, 36A
vein Rs
Wing
Posterior branch of vein R; radial sector (Cumming & Wood 2017).
Fig. 34A
vein Sc
Wing
Slender vein between veins C and R ending on C; subcostal vein
(Cumming & Wood 2017).
Figs 34A, 35, 36A–
C
veinlet (Sorkin & Herman
2018)
Wing
see appendix
vena spuria
Wing
Vein-like thickening of the wing membrane in Syrphidae, extending
between cell br and r4+5; might be evanescent or even absent e.g. Cepa,
Eristalinus sepulchralis, Psilota, some species of Orthonevra, Syritta
flaviventris (Cumming & Wood 2017).
Figs 34A, 37C
ventral (adv. ventrally)
General
On the lower side of a structure; opposite of dorsal (Thompson 1999).
Figs 1C, D, 2, 38B,
54A, B
ventral dens of tergum
IV
Abdomen
Dens-like extension on the ventral margin of tergum IV, as seen in
Nausigaster (Shannon 1922a).
Fig. 47E
ventral postgonite
Male
terminali
a
Additional process connected to the apicoventral wall of the
hypandrium found in e.g. Pipizella and Trichopsomyia; inferior lobe of
gonite; lower gonocercus; ventral gonocercus (Claussen & Hayat 1997;
van Steenis & Lucas 2011; van Steenis et al. 2018a). The true origin of
these structures are under debate and it might be that the structure in
Trichopsomyia is the hamus, while the one in Pipizella is a different
structure. This needs to be evaluated while dealing with the male
genitalia in more detail.
Figs 58B, D
ventral scutellar fringe
Thorax
Row of pile on the apicoventral surface of the scutellum (Thompson
1999).
Fig. 32B
ventral scutellar fringe
(Thompson 1999)
Thorax
see scutellar fringe
vertex
Head
Posterodorsal or uppermost part of the head consisting of the ocellar
triangle and surroundings; in holoptic males this forms a triangular area
(McAlpine 1981).
Figs 6C, D, 7A, D,
8A–C, 9B, C, 12D,
13C
vertexal (Sorkin & Herman
2018)
General
see vertical
vertical
General
Structures of the vertex, thus restricted to features of the head
(Mcalpine 1981; Thompson 1999). Not to be mistaken for the
orientation of the structure.
Figs 6A, C, 7A–C,
8D, 9B, C
vertical carina
Head
Ridge-like structure on the vertex, anterior to the anterior ocellus; only
present in dichoptic specimens (e.g. Melanogaster nigricans and
Sphiximorpha subsessilis).
Figs 8D, 9C
vertical regulae
Head
Linear furrows and upheavals on the exoskeleton, visible as closely set
sulci and carinae on the vertex in genera like Chrysogaster and
Orthonevra (Speight 1987).
Fig. 6A
vertical rugae
Head
Small rounded, depressed spots on the exoskeleton, on the frons of e.g.
Phytomia and Melanogaster (Sorkin & Herman 2018).
Figs 8D, 9C
vertical sulcus
Head
Medial sulcus on the vertex, anterior to the anterior ocellus; mostly
restricted to specimens with the dichoptic condition, e.g. Asarkina
porcina (Thompson 1999).
Fig. 7C
vertical triangle
Head
The vertex, in holoptic males, forms a triangular area with in some
genera a very specific shape (after Thompson 1999).
Figs 6C, 7A, B
Vestibular membrane
(Shatalkin 1981)
Female
terminalia
see sternum IX
vestiture
General
Articulated and non-articulated coverings of the exoskeleton; divided
into macrotrichia and microtrichia (Thompson 1999).
Fig. 4

JvS 2023 2(4): 1–99 Van Steenis et al Syrphidae terminology
36
vitta (pl. vittae, adj.
vittate)
General
A longitudinal (placed lengthwise, anterior-posterior) stripe (Thompson
1999).
Figs 9D, 53E, F
vulva (Kotrba 2000)
Female
terminalia
see secondary gonopore
Wing
Wing
Membranous flight organ (Thompson 1999).
Figs 1A, 3B, 32A,
D, 33D, 34–37
wing length
General
Length of wing measured from basicosta to apex (Thompson 1999).
Arrows in Fig. 1A
zygoma (Collins & Halstead
2008)
Head
see parafacia
Discussion
Many terms are combinations of a certain body part with a certain extension of the
exoskeleton like ‘femoral tubercle’ or ‘posterolateral spina of abdomen’. Many species will
have similar extensions found on other body parts, which are not listed here, and it is advised
to adopt the general construction of terms used here to describe the specific situation in other
species.
The male and female terminalia comprise many structures, external and internal, not
studied in depth in the present work and it is very likely that more terms are needed to
adequately describe all these parts. We advise to start with the general terminology as
employed here and those given by Shatalkin (1975a, b), Sinclair et al. (1994), Shatalkin
(2012) and Sinclair et al. (2013) to build on further terms for the terminalia. Other relevant
literature, which can be used for this purpose, can be found under the terms listed in the
section terminalia.
Acknowledgments
Martin Speight (Wicklow, Ireland) gave valuable comments during the initial phase of this
project. Ana Grković, Snežana Radenković and Ante Vujić (Novi Sad, Serbia), Lisa Fisler
(Neuchâtel, Switzerland), Antonio Ricarte (Alicante, Spain), Jirka Hadrava (České
Budějovice, Czech Republic) Libor Mazánek (Jívová, Czech Republic) and Wouter van
Steenis (Breukelen, The Netherlands) gave valuable comments on the draft terms and figures.
Gunilla Ståhls (Helsinki, Finland) hosted the online meetings. The following curators are
acknowledged: Chris Grinter and Jere Schweikert (San Francisco, USA); Francisco Limeira
de Oliveira (Caxias, Brazil); Steven Paiero (Guelph, Canada); Ante Vujić (Novi Sad); Márcio
Luiz de Oliveira (Manaus, Brazil); Marcia Couri (Rio de Janeiro, Brazil); Freddy Bravo (Feira
de Santana, Brazil); Pasquale Ciliberti (Leiden, the Netherlands) and Olga Ovchinnikova and
Nikolai Paramonov (St Petersburg, Russia). Finally, the three reviewers; Brad Sinclair
(Ottawa, Canada), Menno Reemer (Leiden, the Netherlands) and Martin Hauser (Sacramento,
USA) are acknowledged for their good job in going through the manuscript and comments on
the use of several of the terms.
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1
1
Figure 1. Syrphidae orientation. A, B, D dorsal view; C lateral view. A. Pipizella
ochreobasalis ♀ paratype; Turkey; dorsal view. B, D. Paragus pecchiolii ♀; Serbia; dorsal
view. C. Eristalis arbustorum ♀, Serbia; head, lateral view. A after van Steenis & Lucas
(2011), B–D TT.

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2
2
Figure 2. Syrphidae, ventral half of adult, lateral view. A. Spilomyia manicata ♀; Serbia. B.
Myathropa florea ♂; France. A: TT.

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3
3
Figure 3. Syrphidae. A, lateral view, B–D, dorsal view. A. Ceriana glaebosa ♀; Cyprus. B.
Lycastris cornutus ♂; Taiwan. C. Meromacrus acutus ♂; USA. D. Phytomia bulligera ♂;
Uganda. Scale = 2.0 mm.

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4
4
Figure 4. Different armature and vestiture. GFGM.
5
5
Figure 5. Shapes and angles.

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6
6
Figure 6. Head, dorsal view. A. Lejogaster metallina ♀; The Netherlands. B. Cheilosia
variabilis ♂; Sweden. C. Sphiximorpha subsessilis ♂; Greece. D. Lejota ruficornis ♂;
Sweden. Scale = 1.0 mm.

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7
7
Figure 7. Head, dorsal view. A. Eumerus sulcitibius ♂; Spain. B. Platynochaetus setosus ♂;
Spain. C. Asarkina porcina ♀; Russia. D. Microdon mutabilis ♀; Sweden. Scale = 1.0 mm.

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8
8
Figure 8. Head, dorsal view. A. Spheginobaccha macropoda ♂; Vietnam. B. Pelecocera
caledonica ♀; Sweden. C. Melanogaster nigricans ♂; Russia. D. Melanogaster nigricans ♀;
Russia. Scale = 1.0 mm.

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9
9
Figure 9. Head, A–C, dorsal view, D, anterior view. A. Chrysosyrphus nasutus ♀; Sweden.
B. Lejogaster metallina ♂; Denmark. C. Monoceromyia similis ♀; Taiwan. D. Sphiximorpha
petronillae ♂; Serbia. Scale = 1.0 mm.

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10
10
Figure 10. Head, anterior view. A. Microdon devius ♂; The Netherlands. B. Pipiza luteitarsis
♂; Sweden. C. Xanthandrus comtus ♂; The Netherlands. D. Cheilosia variabilis ♂; Sweden.
Scale = 1.0 mm.

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11
11
Figure 11. Head, anterior view. A. Didea fasciata ♂; Russia. B. Tropidia scita ♂; Sweden. C.
Chrysogaster virescens ♂; Belgium. D. Phytomia errans ♂; Taiwan. Scale = 1.0 mm.

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12
12
Figure 12. Head, lateral view. A. Rhingia campestris ♂; Sweden. B. Chrysosyrphus nasutus
♂; Sweden. C. Cheilosia personata ♂; France. D. Ceriana conopsoides ♂; Russia. Scale =
1.0 mm.

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13
13
Figure 13. Head, lateral view. A. Sphegina latifrons ♂; Germany. B. Pocota personata ♂;
Sweden. C. Leucozona laternaria ♀; Estonia. D. Brachyopa maculipennis ♂; Serbia. Scale A
= 0.5 mm; B–D = 1.0 mm.

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14
14
Figure 14. Head, lateral view. A. Eristalis rupium ♂; Sweden. B. Volucella zonaria ♂;
France. C. Ornidia obesa ♂; Surinam. D. Toxomerus geminatus ♂; USA. Scale = 1.0 mm.

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15
15
Figure 15. Head, A, B, lateral view, C, D, posterior view. A. Ceriogaster spp. ♀; Panama. B.
Nausigaster tuberculata ♀; Brazil. C. Xanthandrus comtus ♀; France. D. Eumerus ornatus ♀;
France. Scale = 1.0 mm.

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16
16
Figure 16. Head, A, C, posterior view, B, D, ventral view. A. Merodon serrulatus ♂;
Montenegro. B. Asarkina porcina ♀; Russia. C. Brachyopa testacea ♂; Russia. D.
Neocnemodon vitripennis ♂; The Netherlands. Scale = 1.0 mm.

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17
17
Figure 17. Head, ventral view. A. Parhelophilus crococoronatus ♂; Spain. B. Brachyopa
bicolor ♂; The Netherlands. C. Platycheirus naso ♂; Sweden. D. Brachypalpoides lentus ♂;
Sweden. Scale = 1.0 mm.

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18
18
Figure 18. Antenna, lateral view. A. Microdon miki ♂; Hungary. B. Platynochaetus setosus
♂; Spain. C. Merodon albifrons ♂; Spain. D. Eumerus grandis ♀; France. E. Callicera
macquarti ♂; Cyprus. Scale A, B, E 1.0 mm; C, D = 0.5 mm.

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19
19
Figure 19. Antenna, lateral view. A. Korinchia tenax ♂; Malaysia. B. Brachyopa scutellaris
♂; The Netherlands. C. Pelecocera tricincta ♀; Sweden. D. Pipiza luteitarsis ♂; Sweden.
Scale A = 1.0 mm; B–D = 0.5 mm.

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20
20
Figure 20. Antenna, lateral view. A. Volucella inanis ♂; Sweden. B. Sphecomyia vespiformis
♂; Russia. C. Cheilosia personata ♂; France. D. Psarus abdominalis ♂; France. Scale A, B =
1.0 mm; C, D = 0.5 mm.

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21
21
Figure 21. Antenna, lateral view. A. Copestylum lentum ♂; USA. B. Masarygus palmipalpus
♂; Holotype. C. Hammerschmidtia ferruginea ♀; Sweden. D. Cacoceria willistoni ♂;
Argentina. Scale A, D = 1.0 mm; B, C = 0.5 mm.

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22
22
Figure 22. Mouthparts, lateral view. Eristalis arbustorum ♀. after Gilbert & Jervis 1998 from
Schiemenz 1957

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23
23
Figure 23. Thorax, A, anterior view, B, dorsal view, C, lateral view, D, latero-dorsal view. A,
B. Volucella pellucens ♀; Serbia. C. Copestylum spp. ♀; Brazil. D. Syrphus phaeostigma ♂;
Argentina. A, B: TT; C, D: GFGM.

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24
24
Figure 24. Thorax, dorsal view. A. Microdon mutabilis ♀; Bosnia-Herzegovina. B.
Sphaerophoria scripta ♂; Serbia. C. Pipiza larusi ♂; Greece. D. Sericomyia silentis ♀;
Serbia. E. Spilomyia manicata ♀; Serbia. All TT.

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25
25
Figure 25. Thorax, anterior view. A. Spheginobaccha macropoda ♂; Vietnam. B. Portevinia
maculata ♂; Sweden. C. Pipizella ochreobasalis ♂ paratype; Turkey. D. Merodon aereus ♂;
Montenegro. Scale = 1.0 mm.

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26
26
Figure 26. Thorax, anterior view. A. Ceriana conopsoides ♂; Russia. B. Sphegina latifrons
♀; Germany. C. Xanthogramma dives ♂; Greece. D. Xanthandrus comtus ♀; France. Scale A,
C, D = 1.0 mm; B = 0.5 mm.

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27
27
Figure 27. Thorax, posterior view. A. Brachyopa insensilis ♂; The Netherlands. B.
Chrysotoxum elegans ♂; France. C. Sphegina verecunda. ♀; Serbia. D. Neoascia tenur ♂;
Russia. Scale = 1.0 mm.

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28
28
Figure 28. Thorax, lateral view. A. Eumerus ornatus ♀; France. B. Portevinia maculata ♂;
Sweden. Scale = 1.0 mm. S I = sternum I.

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29
29
Figure 29. Thorax, lateral view. A. Brachyopa testacea ♂; Russia. B. Ceriana conopsoides
♂; Russia. Scale = 1.0 mm. T I = tergum I, S I = sternum I.

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30
30
Figure 30. Thorax, lateral view. A. Neoascia tenur ♂; Germany. B. Sphegina latifrons ♀;
Germany. Scale = 1.0 mm.

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31
31
Figure 31. Thorax, ventral view. A. Tropidia scita ♂; Sweden. B. Caliprobola speciosa ♂;
The Netherlands. Scale = 1.0 mm.

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32
32
Figure 32. Thorax, lateral view. A. Postalar wall and carina, Xanthogramma dives ♂; Greece.
B. Posterior part of pleura, Xanthogramma dives ♂; Greece. C. Posterior part of pleura,
Spheginobaccha macropoda ♂; Vietnam. D. Supra alar area and pile tuft, Eristalinus aeneus
♂; Greece. Scale = 0.5 mm.

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33
33
Figure 33. Thorax and wing. A. Spiracular fringe, Palpada vinetorum ♀; Brazil. B. Scutellar
depression, Copestylum chapadense ♀; Panama. C. Scutellar fringe, Pelecinobaccha summa
♂; Brazil. D. Costal chaetotaxy, Milesia apsycta ♂; China. Scale = 0.5 mm. A–C GFGM, D
after Hippa 1990.

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34
34
Figure 34. Wing, dorsal view. Toxomerus tibicien ♀; Brazil. A. Veins, B. Cells. All GFGM.

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35
35
Figure 35. Wing, dorsal view. A. Aristosyrphus spp ♀; Brazil. B. Sphegina (Asiosphegina)
crucivena ♂ paratype; Myanmar. C. Microdon spp ♀; Brazil. D. Lycastris cornutus ♂;
Taiwan. Scale A, B = 1.0 mm; D = 2.0 mm. All GFGM.
36
36
Figure 36. Wing, dorsal view. A. Orthonevra spp ♀; Brazil. B. Stilbosoma cyaneum ♀;
Chile. C. Stipomorpha apicula ♂; Brazil. D. Palpada langi ♂; Brazil. Scale A = 0.5 mm. All
GFGM.

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37
37
Figure 37. Wing, dorsal view. A. Lyneborgimyia magnifica ♂; Holotype, Tanzania. B.
Eumerus sulcitibius ♂; Spain. C. Arystosyrphus primus ♂; Brazil. D. Nepenthosyrphus
capitatus ♀; Paralectotype N. tobiacus, Sumatra. Scale A after Ssymank et al. 2021, B after
van Steenis et al. 2017, C after Reemer & Ståhls 2013b, D after Hippa 1978.

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38
38
Figure 38. Legs, anterior view. A. Brachypalpus chrysites ♂; Germany. B, C. Merodon
armipes ♂; Serbia. D. Neocnemodon vitripennis ♂; Sweden. Scale A, C, D 1.0 mm; B 0.5
mm.

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39
39
Figure 39. Legs, anterior view. A. Eumerus sulcitibius ♂; Spain. B. Parhelophilus frutetorum
♂; Sweden. C. Xanthogramma dives ♂; Greece. D. Xylota segnis ♂ The Netherlands. Scale =
1.0 mm.

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40
40
Figure 40. Legs, anterior view. A. Microdon devius ♂; The Netherlands. B. Merodon ibericus
♂; Spain. C. Milesia crabroniformis ♂; France. D. Spazigaster ambulans ♂; Georgia. Scale =
1.0 mm.

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41
41
Figure 41. Legs, anterior view. A. Eumerus stackelbergi ♂; Holotype. B. Xylota steyskali ♂;
Taiwan. C. Chalcosyrphus flavipes ♂; Taiwan. D. Eumerus sulcitibius ♂; Spain. Scale A–C =
1.0 mm; D = 0.5 mm.

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42
42
Figure 42. Legs, A, B, D–G, ventral view, C, anterior view. A. Ischiodon aegyptius ♂;
Greece. B. Pyrophaena granditarsa ♂; Sweden. C. Platycheirus aurolateralis ♂; France. D.
Neocnemodon brevidens ♂; Serbia. E. Milesia crabroniformis ♂; France. F. Platycheirus
naso ♂; Sweden. G. Platycheirus scutatus ♂; The Netherlands. Scale A–D, F, G = 0.5 mm; E
= 1.0 mm.

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43
43
Figure 43. Abdomen, dorsal view. A. Microdon devius ♂; The Netherlands. B. Triglyphus
primus ♂; The Netherlands. C. Pipiza luteitarsis ♂; Sweden. D. Asiobaccha spp ♀; Taiwan.
Scale = 1.0 mm.

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44
44
Figure 44. Abdomen, dorsal view. A. Asiodidea nikkoensis ♂; Japan. B. Chrysotoxum
orthostylus ♂; France. C. Eupeodes latifasciatus ♂; Sweden. D. Asarkina spp ♂; Thailand.
Scale = 1.0 mm.

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45
45
Figure 45. Abdomen, dorsal view. A. Neoascia podagrica ♀; The Netherlands. B. Sphegina
latifrons ♂; Germany. C. Eumerus barbarus ♂; Algeria. D. Syritta pipiens ♀; Sweden. Scale
= 1.0 mm.

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Figure 46. Abdomen, dorsal view. A. Ceriana vespiformis ♂; Greece. B. Cerioidini spp ♂;
Papua New Guinea. C. Platycheirus scambus ♂; The Netherlands. D. Parhelophilus
frutetorum ♂; Sweden. Scale = 1.0 mm.

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Figure 47. Abdomen, ventral view. A. Spazigaster ambulans ♂; Germany. B. Neocnemodon
vitripennis ♂; The Netherlands. C. Sphegina latifrons ♂; Germany. D. Eumerus minotaurus
♂; Greece. E. Nausigaster tuberculata ♂; Brazil. Scale = 1.0 mm. s IV = sternum IV.

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Figure 48. Postabdomen, A, C,dorsal view, B, D,ventral view. A, B. Eupeodes corollae ♂;
Greece. C, D. Pyrophaena granditarsa ♂; Finland. Scale = 1.0 mm. s = sternum, t = tergum.

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Figure 49. Postabdomen, A, C, dorsal view, B, D, ventral view. A. Sphaerophoria scripta ♂;
Sweden. B. Orthonevra nobilis ♂; Sweden. C, D. Eristalis abusiva ♂; The Netherlands. Scale
= 1.0 mm. s = sternum.

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Figure 50. Postabdomen, Volucella bombylans; Russia. A. Dorsal view, B. Ventral view.
Scale = 1.0 mm. t = tergum.

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Figure 51. Postabdomen, A, C, dorsal view, B, D, ventral view. A, B. Criorhina brevipila ♂;
Russia. C, D. Temnostoma bombylans ♂; The Netherlands. Scale = 1.0 mm. s = sternum, t =
tergum.

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Figure 52. Postabdomen, female, A–C, dorsal view, D, ventral view, E, lateral view. A.
Ceriomicrodon petiolatus ♀; Brazil. B. Hybobatus phaeopterus ♀; Brazil. C. Sterphus
plagiatus ♀; Brazil. D, E. Ornidia obesa ♀; Brazil.

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Figure 53. Photo. A. Pyrophaena granditarsa ♂; Sweden, mesotarsus, lateral view. B.
Brachyopa bicolor ♂; The Netherlands, apex of metatibia, ventral view. C. Ceriana
ornatifrons ♂; Nepal, face, antero-lateral view. D. Hybobathus rubricosus ♂; Brazil, thorax
dorsal view. E. Sphecomyia vespiformis ♂; Russia, thorax, dorsal view. F. Monoceromyia
tredecimpunctata ♂; India, thorax, dorsal view. Scale A–C = 0.5 mm; E, F = 1.0 mm. D
GFGM. In Figs E and F “vitta” and “fascia” mean that they are non-pruinose and shiny, the
pruinose vitta and fascia are dull.

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Figure 54. Male terminalia, lateral view, A Epandrium, B, D Hypandrium, C Phallus. A–C.
Merodon clavipes; Spain. D. Eumerus obliquus; Angola. Scale A–C = 0.5 mm, D = 0.35 mm.
All GFGM.

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Figure 55. Male terminalia, A–D, lateral view, E,ventral view. A. Epandrium, B.
Hypandrium, C, D. Phallus. E. Hypandrium. A, B. Mimocalla erebus; Brazil. C, D.
Ocyptamus gastrostactus; Colombia. E. Korinchia formosana; Taiwan. All GFGM.

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Figure 56. Male terminalia, lateral view. B, D, F. Phallus. A, B. Ceriana caesarea;
Turkmenistan. C, D. Ceriana conopsoides; Russia. E, F. Rhopalosyrphus spp.; Brazil. Scale
A–D = 0.5 mm. A–D after van Steenis et al. (2016), E, F GFGM.

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Figure 57. Male terminalia, lateral view. B. Phallus. A. Maiana pumila; Peru. B, C.
Orthonevra argentina; Argentina. D. Neocnemodon elongata; Canada. All GFGM.

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Figure 58. Male terminalia, A, E, ventral view, B–D, lateral view. A, D. Hypandrium. C, F.
Epandrium. A. Ceriana conopsoides; Russia. B. Pipizella cantabrica; Spain. C. Pipizella
siciliana; Italy. D. Pipizella ochreobasalis; Turkey. E, F. Trichopsomyia flavitarsis; Sweden.
Scale = 0.5 mm. A after van Steenis et al. (2016), B–D after van Steenis & Lucas (2011), E,
F after van Steenis et al. (2018a).