Williston, 1886: 289 Robber flies (Insecta: Diptera: Asilidae) of Wyoming, USA with keys to genera and species Lavigne, Robert J. Dennis, Steve Zootaxa 2019 2019-08-30 4662 1 1 126 (Williston) Williston Williston 1886 [151,556,1744,1771] Insecta Asilidae Ospriocerus CoL Animalia Diptera 102 103 Arthropoda species aeacidinus     Stenopogon aeacidinus  Williston, 1886: 289.   Recognition characters:Gray and orange species; length 14–20 mm; mystax white; thorax grayish yellow pollinose; meron with fine short setae; wings brown; abdomen yellowish red; segments 1 and 7 black as is segment 6 laterally; legs black to reddish black, bristles and setae black.  Distribution:FREMONT: near Lander,  1,524 –2,438m(  5,000 –8,000ft), July 1895( RM-UK). Recorded from Wyomingby: Geller-Grimm (2018).  Habitat:Sagebrush steppe shrub and grassland vegetation type.  Ethology:Nothing known.  Prey:None known.