Hypselosyrphus is based on an Ubristes species in which the 4th abdominal segment is short and triangular. As with Stipomorpha, this character is considered only of species group value.
Ubristes (Hypselosyrphus) species have postmetacoxal bridge complete; abdomen triangular, broad basally, strongly narrowed apically, short, almost equilateral in shape; metatibia with long pile along dorsal edge, forming a distinct brush of pile; basoflagellomere not furcate, usually not greatly elongate; metabasitarsomere not enlarged; and vein R4+5 with an appendix extending posteriorly into cell R4+5.
Adapted from original description (Shannon 1927).
FEMALE.
Differs considerably from the other species of this subgenus in having the abdomen broadly ovate and the scutellum produced apically and triangular in shape. Head black, front and face unsually narrow, front nearly three times as long as broad, ocellar region protuberant; antennal joints 1: 0.25: 1; arista shorter than basoflagellomere; face narrowed downward, pale pilose, the sides whitish pollinose; thorax dark brown, dark pilose; all the legs dark brown, the apical tarsomeres yellowish; metafemur and metatibia rather slender, long dark pilose, the dorsal incision of tibia broad and rather shallow; metatarsi of much larger girth than either femur or tibia; abdomen brownish, the sides narrowly yellow, second and third terga each with a large pair of yellow maculae; fifth tergum well developed, yellow, with a median, longitudinal, dark vitta; wings large, slightly infuscated, with a median, rather faint, whitish cross vitta.
Shannon (1927) originally described this taxon as Microdon (Ubristes) scutellaris. Hull (1937) created the genus Hypselosyrphus for trigonus Hull. Thompson et al (1976) placed it under Ubristes.
Ubristes (Hypselosyrphus) scutellaris (Shannon, 1927).
Shannon, R.C. (1927) A review of the South American two-winged flies of the family Syrphidae. Proceedings of the United States National Museum 70(9)[= No. 2658], 34 p. [1927.04.29]
unless otherwise stated