Machimus occidentalis (Hine)

Lavigne, Robert J. & Dennis, Steve, 2019, Robber flies (Insecta: Diptera: Asilidae) of Wyoming, USA with keys to genera and species, Zootaxa 4662 (1), pp. 1-126 : 47-48

Machimus occidentalis (Hine)

Machimus occidentalis Hine, 1909:147 .

Recognition characters: Grayish species; length 13–15 mm; mystax black above, white below; thorax brown and gray pollinose; scutellar setae white, 4 bristles, usually black although one or two may be white; wings hyaline with apex and inner margin faintly gray; abdomen gray pollinose with only a faint touch of brown dorsally; lateral setae and bristles on first abdominal segment white; legs black, femora may or may not have a preapical reddish band; tibiae reddish.

Distribution: ALBANY: Laramie, 1.6 km E, numerous records, 24 June–21 July ( RJL, SD); West Laramie, 11 July 1960 ( RJL). FREMONT: near Lander, 1,524 –2,438 m (5,000 –8,000 ft), July and Aug. ( RM-UK); Shoshoni ( FRH, RJL); HOT SPRINGS: Owl Creek Mtns., N end of Wind River Canyon, 1,829 m (6,000 ft), 25 June 1961 ( RJL). LARAMIE: Pine Bluffs ( FRH, RJL). NIOBRARA: Lusk, 19 km N, 64 km N, July 1895 ( RM-UK). PLATTE: Dwyer, numerous records, 1 May–28 June ( DRT, RJL); Glendo, ( FRH, RJL); Guernsey, 8 June 1981 ( RJL); Guernsey State Park, 14 June 1962 ( RJL); Hartville, 24 May–14–19 June 1963 ( RJL); Wheatland, 24 May–26 Aug. ( FRH, RJL). SWEETWATER: Rock Springs, 6, 9 June 1958 ( JW) (as M achimus hinei Fisher & Wilcox 1997 , three speci- mens in CAS). UINTA: Lyman, 25 June 1935 ( JB) (as Machimus hinei , specimen in CAS). TETON: Jenny Lake, Grand Teton National Park, July 1931 ( VMT-BYU); Jenny Lake Grove, Grand Teton National Park, 20–30 June 1941 ( GEB-UCD). Recorded from Wyoming by: Dennis & Lavigne (1979) (as Machimus occidentalis ); Geller- Grimm (2018); Lavigne & Pfadt (1964, 1965, 1966) (as Asilus occidentalis ; grasshopper predator).

Habitat: Sagebrush steppe and wheatgrass-needlegrass shrub steppe shrub and grassland, and grama-needlegrass-wheatgrass grassland vegetation types. Protected gullies with Pinus ponderosa cover; short- to mid-grass plains and areas where Artemisia tridentata is dominant ( Dennis & Lavigne 1979); rangeland breaks with coniferous forest ( Martin 1975).

Ethology: Forages from both the ground and vegetation, depending on the temperature of the ground (see Dennis & Lavigne 1979).

Prey: DIPTERA , HYMENOPTERA , ORTHOPTERA (see Dennis & Lavigne 1979; Lavigne & Pfadt, 1966, as Asilus occidentalis ).