Stenopogon graminis Lavigne & Dennis, 2019

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 : 108-109

Stenopogon graminis Lavigne & Dennis sp. nov.

Holotype male: Length 23 mm.

Head: black and orange ground color; face and occiput densely gray tomentose, frons golden pollinose; proboscis black except mediolateral slanted yellowish white stripe preceded by reddish brown area; first papal joint black; second joint orange with apical black ring. Mystax, beard, occipital bristles, setae of palpi and proboscis straw white; bristles of frons and ocellar tubercle reddish brown. Antennae black except second segment and apical 2/3 first segment orange, the second 11/27 the length first. Two together 27/30 length third segment. Style 2/3 length third segment; bristles of antennae straw white except those above on first segment reddish brown.

Thorax: mesonotum with central dark brown tomentose stripe and contiguous dark brown tomentose spot anteriorly, humerus orange tomentose, otherwise yellowish brown, central stripe narrowly bisected by yellowish tomentose median stripe. Bristles of pronotum straw white; those of mesonotum short, reddish brown anteriorly, and long, straw white posteriorly and dorsolaterally. Pleura and coxae golden gray tomentose; bristles of proepimeron, katepisternum, metapleura and coxae straw white, katepisternum posteriorly with long, fine, straw white setae. Scutellar disc densely golden gray tomentose, marginal bristles straw white.

Wings: hyaline, first and fourth posterior cells open; macrotrichia of costal vein brownish white, considerably longer base of costa; anterior cross vein 21/47 length discal cell. Halteres straw white darkening to light brown base of stem.

Legs: bicolored, front femora dorsally, basal half anteriorly and narrow stripe dorsally of mid-femora, anterior and stripe posteriorly apical half hind femora, two thirds of fore tibiae dorsally, apical half and anterior side midtibiae, apical 5/7 ventral side, apical half of dorsal side, anterior and posterior sides hind femora black, remainder reddish brown. Bristles and setae straw white. Claws black, basal third reddish brown; empodium reddish brown; pulvilli straw white.

Abdomen: bicolored, tergites 2–5 gray pollinose with narrow orange pollinose ring both basally and preapically, tergites 6–7 with basal ring only, tergites 4–7 with median orange pollinose stripe; setae and bristles straw white, those bristles tergite 1 and laterally tergites 2–4 stout and longer than remaining segments; genitalia shining reddish brown, epandrium pointed apically with reddish brown bristles, hypandrium bilobed apically with deep cleft between lobes, bristles straw white.

Female: Length 23 mm. Similar to male. Head more orange ground color. Bristles frons straw white. Reddish brown area on proboscis more extensive and mediolateral stripe less distinct. All antennal segments including style orange. Second segment 9/23 length first, two together 23/28 length third segment, style 17/28 length third segment. Abdominal tergites 6–8 shining bicolored black and reddish brown, setae of genitalia short, straw white, apical spines reddish brown. Hind femora black except basal 2/5 ventrally reddish brown, basal half tibiae, basal 2/5 mid- tibiae and basal third posteriorly hind tibiae reddish brown, remainder black. Anterior cross vein 21/41 length discal cell.

Holotype, male: Platte County, Wyoming: Dwyer , 23 June 1966 / R.J. Lavigne (deposited in USNM).

Paratypetype, female: Platte County, Wyoming: Dwyer, 1 July 1964 /F.R. Holland (deposited in USNM).

Paratypes, Platte County, Wyoming: two females, 3, 7 July 1964; Dwyer, four females, 1 July 1960 /R.J. Lavigne; 7 July 1960 /R.J. Lavigne, 28 June 1961 /R.J. Lavigne (two specimens); Jack Jones Ranch, Dwyer, two females, 30 June 1964 /R.J. Lavigne; Glendo, female, 9 July 1964; Guernsey, male, 6 July 1951 / GRD; male, two females, mated pair, 28 June 1961 /R.J. Lavigne; mated pair, 27 June 1962 /R.J. Lavigne; male, 15 July 1962 /R.J. Lavigne; male, 28 June 1963 /R.J. Lavigne; Frederick Ranch, Guernsey, mated pair, 6 July 1964 /R.J. Lavigne; female, 16 July 1964 /R.J. Lavigne; Wheatland, female, 30 June 1964 /?, female, 3 July 1964 /?, female, 8 July 1964 /? (all specimens deposited in the senior authors collection).

Certain characters vary within the type series. The color of the bristles of the frons and ocellar tubercle range from straw white to reddish brown. The extent of orange coloration of the antennal segments varies considerably as does the coloration of the abdominal tergites that ranges from all gray pollinose to mostly orange. The extent of black on the legs also varies somewhat among the type specimens.

Distribution: PLATTE: 3, 7 July 1964; Dwyer, 1, 7 July 1960 ( RJL); 28 June 1961 ( RJL); 1 July 1964 ( FRH); 23 June 1966 ( RJL); Jack Jones Ranch, Dwyer, 30 June 1964 ( RJL); Glendo, 9 July 1964; Guernsey, 6 July 1951 ( GRD); 28 June 1961 ( RJL) (three specimens); 27 June 1962 ( RJL); 15 July 1962 ( RJL); 28 June 1963 ( RJL); Frederick Ranch, Guernsey, 6July 1964 ( RJL) (two specimens); 16 July 1964 ( RJL); Wheatland, 30 June 1964; 3, 8 July 1964.

Habitat: Grama-needlegrass-wheatgrass grassland vegetation type.

Ethology: Nothing known.

Prey: COLEOPTERA , Scarabaeidae : Guernsey, 28 June 1963, male with Aphodius fossor (L.) as prey ( RJL). DIPTERA , Asilidae : Dwyer, 28 June 1961, female with Ospriocerus abdominalis female as prey ( RJL); 1 July 1964, female with Ospriocerus abdominalis male as prey ( FRH). Guernsey, 15 July 1962, male with Scleropogon coyote (as Stenopogon coyote ) male as prey ( RJL). Frederick Ranch, Guernsey, 6 July 1964 female with Pogonioefferia staminea (as Efferia staminea ) male as prey ( RJL). ORTHOPTERA , Acrididae : Guernsey, 28 June 1961, female with Aeropedellus clavatus (Thomas) male as prey ( RJL); 28 June 1961, female with Melanoplus confusus Scudder male as prey ( RJL).