Helcogramma includes 12 species: H. billi n. sp., H. capidata Rosenblatt, 1960, H. chica Rosenblatt, 1960, H. decurrens McCulloch and Waite, 1918, H. ellioti (Herre, 1944), H. fuscopinna Holleman, 1982, H. hudsoni (Jordan and Seale, 1906), H. obtusirostris (Klunzinger, 1871), H. rhinoceros n. sp., H. springeri n. sp., H. steinitzi Clark, 1979, and H. striata n. sp. Helcogramma trigloides is ... [Show full abstract] regarded as a species inquirendum; no specimens of this species were found. The four new species are figured in whole lateral view. Ail species are figured in detailed head views to show characteristics of cephalic sensory canals (dorsal and ventral). My study confirms that all members of the family Tripterygiidae share a single specialization: Loss of the posteriormost spine of the second dorsal fin. Members of the genus Helcogramma share the following character: A single lateral line, composed of 12-37 pored scales curving down from the posttemporal bone, behind the pectoral fin and continuing along the midline of the body. Some characters of the osteology of Helcogramma are discussed and figured in the diagnosis of the genus.