Osten-Sacken, 1887: 206 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 4MPLT (Osten-Sacken) Osten-Sacken Osten-Sacken 1887 [151,636,1190,1217] Insecta Asilidae Proctacanthella Animalia Diptera 55 56 Arthropoda species exquisita     Proctacanthus exquisitus  Osten-Sacken, 1887: 206.   Recognition characters:Yellowish gray species; length 19–25 mm; mystax white; thorax yellow gray pollinose; scutellar setae and bristles pale yellowish white; wings subhyaline; abdomen yellowish gray; male hypandrium with a medial fan of white setae on each side; female eighth abdominal segment reddish brown; legs fore and mid femora reddish, hind femora black with posterior reddish stripe, tibiae dark reddish to black, densely covered with white setae, bristles mostly whitish.  Distribution:FREMONT: Lander, WANG, LTA, 2 July 2005( CSU, GMAD).  Habitat:Wheatgrass-needlegrass shrub steppe shrub and grassland vegetation type.  Ethology:Nothing known.  Prey:None known.