Hemipenthes pleuralis (Williston)

Ávalos-Hernández, Omar, 2009, A review of the North American species of Hemipenthes Loew, 1869 (Diptera: Bombyliidae), Zootaxa 2074, pp. 1-49 : 33-34

16. Hemipenthes pleuralis (Williston)

(Figs. 18, 63–64)

Anthrax pleuralis Williston, 1901: 282

Villa (Hemipenthes) pleuralis (Williston) : Painter & Painter, 1962: 121. Hemipenthes pleuralis (Williston) : Hull, 1973: 386.

Holotype female in BMNH.

Diagnosis: Cell r1, r2+3, dm, and a entirely infuscated or just hyaline at tip; mesopleuron and sides of first abdominal tergite white or yellow pilose; fifth abdominal tergite with a band of white scales covering the whole tergite.

Description: Male. Body length: 10–12 mm; wing length: 9–11 mm. Head: Eyes separated by a little more than width of ocellar triangle. Front black pilose, black tomentose. Face cinereous, rounded, with black hairs and white tomentum. Scape black, swollen on inner apical margin, with black hairs, twice as long as pedicel; pedicel black, twice as wide as long, with short black hairs in dorsal portion, bare in ventral portion; flagellomere black, longer than scape and pedicel combined; base subconical, tapering to styliform apical two-thirds; stylus minute, terminal. Proboscis short, not projecting beyond oral margin. Palpi black with black hairs. Occiput with short yellowish hairs and white scales.

Thorax: Mesonotum anterior margin yellowish pilose; lateral margin entirely black pilose; tomentum on disc black, yellow near scutellum; bristles black. Mesopleuron yellow pilose on proepisternum and katatergite, anepisternum with black hairs, katepisternum not tomentose, black pilose. Proepimeron with white hairs. Mid coxa with black hairs, coxae without tomentum. Legs brown, tarsi black, femora black pilose black tomentose on anterior surface and white tomentose on posterior surface; bristles black. Halter steam and knob yellow. Scutellum brown, not pilose, black tomentose; bristles black. Black setulae on basicosta. Cells c, sc, br, bm, and r1 entirely infuscated (Fig. 18); cells r2+3, dm, a, and cup entirely infuscated except tip; cells r5 and cua1 with basal half infuscated; cells m2 and r4 infuscated just at base; cell dm infuscated beyond r-m crossvein; r-m crossvein at or slightly behind middle of cell dm; no crossvein between R4 and R2+3; cell r5 slightly narrowed at wing margin; first section of vein CuA1 two and a half the long of r-m crossvein, second section twice the long of r-m crossvein, third section as long as the first two sections combined; cell a twice wider than cell cup; alula well developed.

Abdomen: Abdominal dorsum with yellowish pile on tergite one, rest black pilose; black tomentum overall, white scales on fifth to seventh tergites covering the whole tergite; sides of abdomen with first and basal half of second tergites yellowish pilose, black hairs on third, fourth and apical half of second tergites, rest not pilose. Venter white pilose on first to third sternites, rest black pilose, with stripes of white and black tomentum. Genitalia brown with black hairs. Epandrium in lateral view, triangular, lower margin straight, basal corner narrowed; gonocoxite broad, basal half enlarged; gonostylus large, as long as half the width of the gonocoxite, hooked apically; epiphallus in lateral view narrow ( Fig. 63 ) slightly curved, not cap-shaped, apex not swollen, rounded; with a ventral extension broad at base with apex rounded, portion of the epiphallus behind ventral extension shorter than aedeagus; epiphallus in ventral view broad ( Fig. 64 ), lateral margins straight, without spines; aedeagus broad at base narrowed at apex, swollen dorsally; gonopore terminal.

Female. Nearly identical to male. Eyes separated by twice width of ocellar triangle. Mesonotum lateral margin yellow pilose. Anepisternum with white hairs. Tomentum on katepisternum white. Tomentum on coxae white. Scutellum black tomentose, yellow scales along posterior margin. Cell r5 not narrowed at wing margin. Abdominal dorsum with a crossband of yellowish tomentum on apical half of first tergite, fifth to seventh abdominal tergites with yellow and white scales on sides, not reaching tergite center.

Distribution: Mexico (Chiapas, Colima, Guerrero, Morelos, Nayarít, Puebla, Sinaloa, Tamaulipas).

Specimens examined: Mexico. Colima: 5 mi E Colima Hy 110 km 212, 27 -VIII-1962, C.H. Martin (1 male genitalia; USNM); 1 mi S Colima, 25-VIII-1962 (3 males; USNM). Tamaulipas: Gomez Farías y Vic., 20-24-VI-1965 Cornell Univ. Mexico Field Party (3 females; USNM).

Remarks: Hemipenthes pleuralis is related to H. celeris , H. curta , and H. martinorum as all these species have the same genital structure and similar wing pigmentation, with a smooth color margin, not sinuous as other species in the genus. Hemipenthes pleuralis is distinguished from these species by the pigmentation on cells r1, r2+3, dm, and a, which are entirely infuscated or just hyaline at the tip. Hemipenthes pleuralis is present only in Mexico, although it is similar to the South American species H. galathea , which is found in Costa Rica. Externally, H. pleuralis and H. galathea are almost identical and may be synonyms, but genitalia and type studies of both species are necessary to clarify the relationship.

Figures

FIGURES 63 – 64. Hemipenthes pleuralis male terminalia. 63, lateral view; 64, ventral view.