Plesiomma angustum (Macquart)

Scarbrough, Aubrey G. & Perez-Gelabert, Daniel E., 2006, A review of the asilid (Diptera) fauna from Hispaniola with six genera new to the island, fifteen new species, and checklist, Zootaxa 1381, pp. 1-91 : 73-76

Plesiomma angustum (Macquart)

( Table 1, Figs. 91–97)

Dasypogon angustum Macquart, 1848: 20 . Type locality: Haiti, type :?

Plesiomma angustum (Macquart) . Hull, 1962: 219; Martin & Papavero 1970: 21. Catalogue.

Redescription, male. Brownish-yellow or yellow. Measurements, body 11.6–13.1mm; wing 8.9–9.0 mm. Head: Black dorsally, brown or brownish yellow ventrally. Face brownish-yellow tomentose; oral margin with one row of yellow or reddish bristles. Palpus yellow, yellow setose. Proboscis black, middle 1/2 ventrally yellowish; yellowish setose. Antennae black setose; scape and pedicel yellow, about same length, scape not unusually swollen; flagellum black with sparse black setae dorsally, about as long as pedicel and scape combined, about twice as long as either scape or pedicel. Frons and ocellar tubercle dark brown tomentose, slightly yellowish at some light angles; ocellar setae black. Vertex wide, about 1/2 as wide as face at antennae; vertex posteriorly yellowish tomentose, narrow brown tomentose stripe from base of ocellar tubercle posteriorly sometimes present. Occiput yellow tomentose, grayish medially and ventrally; postocular bristles and setae yellow, ventral setae pale yellow.

Thorax: Prothorax mostly black, brown or yellowish-brown tomentum, propleuron yellow, bright yellow tomentose; stout yellow bristles dorsally, whitish long setae laterally. Scutum with 3 black stripes dorsally, blackish or brown tomentose, lateral stripe shorter than median stripe and divided transversally and separated from median stripe by wide yellow or golden yellow tomentose line; median stripe extends forward to pronotum and divided longitudinally by faint, narrow, yellowish-brown tomentose line; ground color yellow on each side of median stripe anteriorly and wide margin laterally; vestiture mostly yellow or reddish, stout bristles mostly black or black tipped; setae scattered anteriorly and laterally in yellow areas, longitudinal row of short acrostichal setae and bristly dorsocentral setae present, 2–5 of latter long, often blackish. Scutellum and mediotergite black, brown tomentose; 2–3 marginal scutellar bristles present, reddish or black tipped. Mesopleuron mostly black, dorsoposterior corner of katepisternum, anepisternum posteriorly, anatergite, katatergite, and metapleuron yellow, latter usually bright yellow tomentose; wide dark brown tomentose stripe extends across the anepisternum and katepisternum anteriorly, yellowish-gray tomentose posteriorly; katatergal bristles thin, either yellow or black. Halter yellow.

Wing: Dense blackish microtrichose, darkest anteriorly; microtrichia brownish present medially. Veins mostly brown, costa black, veins at base of wing yellowish, color often extending toward middle of wing.

Legs: Mostly yellow, black setose, bristles yellow or reddish. Coxae mostly yellow and yellowish tomentose, fore and middle coxae anteriorly and hind coxa laterally black except narrow apex; fore coxa blackish tomentose anteriorly; vestiture pale with sparse black setae. Trochanters blackish apically, yellow or yellowish brown basally. Basal 1/2 of fore and middle femora with blackish anteroventral stripe; hind femur and hind tibia with preapical bands or anterior black spot. Tarsi yellow, apical tarsomeres slightly brownishyellow; black setose, and black and reddish bristles. Claws black, pulvilli gray.

Abdomen: Spatulate, tergites 6–7 only slightly wider than junction of 2–3 yellow, black setose. Tergites 1–4 or 5 sooty black basally; narrow lateral margins of tergites 2–8 black; tergites 6–8 with short black line medially. Setae short dorsally, long on sternites and tergites 1–2 laterally, latter bristly.

Terminalia ( Figs. 91–95): Rotated 90 o, yellow with hypandrium black basally, black setose.

Female. Measurements, body 13.3–15.1 mm; wing 9.9–11.2 mm. Identical to male except narrow apical margins of segments 6–8 black. Terminalia ( Figs. 96–97). Sternite 8 medially with long, thin setae. Genital fork Y-shaped. Spermathecae long, extending to base of segment 5, each narrow, darkly sclerotized, tightly coiled 7 times apically.

New records. DOMINICAN REPUBLIC: prov. La Altagracia, / Nisibon, 4–7.v.78 / beach under coconuts ~ G.B.Fairchild & / R.E.Woodruff / insect light trap (1 ♂, 1 ♀, FSCA); RD-187 near Uvero, Rd. to / Playa Buen Hombre [Montecristi province], 200 m. / 7.xii.2003, D.Perez, R. Bas- / tardo, A. Marmolejos (7 ♂, 4 ♀, MHND, USNM); RD-264 Km. 25 rd Cabo Rojo / - Aceitillar, Pedernales prov. / 678 M, 10.vii.2004, D.Perez (1 ♀, USNM) .

Distribution. Captured during May, July, and December in La Altagracia, Montecristi, and Pedernales provinces, Dominican Republic, and in Haiti.

Remarks. Plesiomma angustum is distinguished from congeners by the characters in the key, the proboscis is mostly yellow ventrally, and the combined characters of the terminalia ( Figs. 91–97).

This is the first report of P. angustum from Hispaniola since its original description in 1848. Although, the type specimen has been 'lost' ( Martin & Papavero, 1970), these specimens have a quite narrow abdomen as its name implies. A comparison of these Hispaniolan specimens with valid West Indian Plesiomma species suggests that it is endemic to Hispaniola. Though we are uncertain of the type locality in Haiti (possibly Port-au-Prince vicinity), new material adds La Altagracia, Montecristi, and Pedernales provinces, Dominican Republic, to its distribution. Collecting records suggest that it occurs at low elevations (sea level to 700 m).