Promachus dimidiatus Curran, 1927

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 : 59-60

Promachus dimidiatus Curran

Promachus dimidiatus Curran, 1927: 87 .

Recognition characters: Grayish black species; length 18–25 mm; mystax yellowish; thorax with a pair of narrow median grayish or pale yellow longitudinal stripes on anterior three-fourths and a broad, suturally interrupted one on either side; scutellar setae long sparse white, bristles in male black, female 3–4 pairs of black bristles, the other yellowish; wings tinged yellowish brown especially towards apex; abdomen in male partly shining black on 2–4, 1–2 and 4–5 mostly white setae with few black setae, 6–8 with considerable black setae; female wholly pale setae; legs dark rusty reddish, gray pollinose, setae white with a few black setae, bristle black.

Distribution: FREMONT: Poison Creek, numerous records, 21 June–22 July ( FRH, RJL, LJS); Shoshoni, 11 km SW, 21–25 June 1973 ( SD). NIOBRARA: Lusk, 19 km NW, July 1895 ( RM-UK). PLATTE: Dwyer, 25 June 1958 ( DRT), 13, 17 July 1959 ( RJL), 13 June 1965 ( FRH), 13 July 1966 ( RJL); Glendo, 10 July 1963 ( LFS); Gray Rocks Ranch, Camp Guernsey, WANG, 14 July–5 Aug. 2008 ( CSU, GMAD); Guernsey, 13 July 1961 ( RJL); Wheatland, 27 July 1965 ( FRH); 35 km W of Wheatland, 9 July 1981 ( RJL). Recorded from Wyoming by: Dennis & Lavigne (1975) (as prey of Stenopogon inquinatus ), 2007; Dennis et al. (2010); Geller-Grimm (2018); Lavigne & Holland (1969) (as prey of Diogmites angustipennis ; voucher specimen #14); Tomasovic (2013) (personal communication).

Habitat: Sagebrush steppe shrub and grassland, and grama-needlegrass-wheatgrass grassland vegetation types. Open range, short grass plains area and protected gullies with pine (see Lavigne & Holland 1969); dry intermittent streambed in weedy area adjoining open rangeland.

Ethology: In early morning and late afternoon forages from the soil when soil temperatures are less than 56°C; during midday forages 45 cm or higher above the ground on vertical stalks of shrubs (general, Lavigne & Holland 1969; courtship, Lavigne 2003).

Prey: All records were collected on 23 June 1966 at Dwyer, Wyoming except as noted. DIPTERA , Asilidae : Efferia sp. (male- two records), Scleropogon coyote ; Tachinidae : Dinera grisecens (Fall.) ; HETEROPTERA, Coreidae : Alydus eurinus Say ; HYMENOPTERA , Apidae : Apis mellifera L., 31 July 1959; Megachilidae : Megachile sp., Shoshoni, 11 km SW, 21 June 1973; Sphecidae : Podalonia luctuosa (Smith) ; Sphex procerus (Dahlborn) , 11 km SW of Shoshoni, 25 June 1973. [ COLEOPTERA , DIPTERA , HETEROPTERA (as Hemiptera ), HYMENOP- TERA, LEPIDOPTERA (see Lavigne & Holland 1969)].