Cyrtopogon bimaculus (Walker)

Euramostus bimacula Walker, 1851: 102 .

Recognition characters: Blackish species; length 9–13 mm; third antennal segment black; mystax white with black bristles above and below; thorax shining black with large brown pollinose areas; wings hyaline except brown cloud at wing apex and apex of anal cell of male, macrotrichia of costal vein black; scutellar setae black; abdomen shining black, gray pollinose fasciae interrupted on all tergites; lateral setae on abdominal segments 1–4 yellowish white; legs, femora black, tibiae reddish orange with apical black ring.

Distribution: ALBANY: Centennial, 5 Aug. 1938 (EH-OSU); Laramie, 31 July 1946 (DGD); Libby Creek, Snowy Range Mtns., 18 June 1961 (RJL); 24 June 1962 (RJL); 22 June 1972 (SD); 15 July 1938 (MJ-CSU); Pole Mtn., 30 July 1950 (DGD); Snowy Range Mtns., 4 July 1948 (DGD); 17 July 1949 (DGD); 28 July 1955; Univ. of Wyoming Summer Camp, Medicine Bow Range, Aug. 1929 (TDAC); 3,292 m (10,800 ft), Libby Creek Drainage, Medicine Bow National Forest, 5 Aug. 1978 (CDF); CARBON: Bottle Creek Campground, Sierra Madre Mtns., 5 July 1963 (RJL) ( Cyrtopogon bimacula male as prey of Scleropogon sp. female); Elk Mtn., 23 July 1971 (RJL) (courting pair on ground/in vegetation/by log 3 pm), 11 July 1972 (SD, RJL). LINCOLN: Commissary Ridge, near Cokeville, 17 June 1959 (WDF). PLATTE: Dwyer, 1 June 1961 (RJL). SHERIDAN: Big Horn Mtns., 2.5 km NE of top of Granite Pass, elevation 2,690 m (8,825 ft), 25 July 1964 (HBL) (12 specimens in CAS); Duncum Mtn., elevation 2,652 –2,865 (8,700 –9,400 ft), 26 July 1964 (CD) (specimen in CAS). TETON: Grassy Lake, Targhee National For., 2 Aug. 1972 (RJL). YELLOWSTONE NATIONAL PARK: 11 km NW of Continental Divide on Highway 16, 19 July 1964 (JW) (specimen in CAS), USA /4901N 529.0E, 14 July 1990, Malaise trap. Recorded from Wyoming by: Adisoemarto (1967) (YNP); Cole (1969) (as Cyrtopogon bimacula); Geller-Grimm (2018); Melander (1923b) (as Cyrtopogon bimacula); Wilcox & Martin (1936).

Habitat: Douglas fir forest and pine-douglas fir forest, sagebrush steppe shrub and grassland, and gramaneedlegrass-wheatgrass grassland vegetation types.

Ethology: Rests on and forages from soil, rocks and fallen logs.

Prey: DIPTERA, Culicidae: unidentified, Grassy Lake, Targhee National For., 2 Aug. 1972; Libby Creek, Snowy Range Mtns., 22 June 1972; PSOCOPTERA, Mesopsocidae: Mesopsocus unipunctatus (M̹ller), Grassy Lake, Targhee National For., 2 Aug. 1972.