Geron nevadensis Hall & Evenhuis

Hall, Jack C. & Evenhuis, Neal L., 2003, Review of the subgenus Geron (Geron) Meigen in the Nearctic Region (Diptera: Bombyliidae: Toxophorinae), Zootaxa 181, pp. 1-72 : 40-41

Geron nevadensis Hall & Evenhuis , sp. nov.

Description. Male. Head. Front silvery white tomentose, pile wanting; antenna black; scape white haired; pedicel with short black hair apically; first flagellomere narrow, evenly tapering from base to acuminate apex; antennal ratio: 14:5:28; face cinereous pollinose, white pilose, bare medially, silver­white tomentum lateral to antennal base; oral margin pale; proboscis projects beyond oral margin for a distance approximately two times head height; gena white pilose and tomentose; occiput white pilose, lower half with white tomentum; ocellar tubercle with mixed white and black hair.

Thorax. Mesonotum velvety black; side narrowly cinereous pollinose; median longitudinal stripe not evident; notum entirely white pilose, tomentum wanting; pleura white pilose and tomentose; legs black, mid and hind tibiae vaguely ferruginous, legs white pilose and tomentose; halter with stem and knob pale yellow; scutellum white pilose, tomentum wanting.

Wing. Hyaline; venation normal; crossvein r­m slightly beyond middle of cell dm; vein m­cu slightly sinuous; basicosta with white hair.

Abdomen. Dorsum white pilose and tomentose, tomentum tending toward silver; side and venter white pilose and tomentose; lateral margins of tergites and posterior margins of sternites narrowly pale.

Genitalia ( Fig. 44 ) with gonocoxa in ventral view with two pits separated by a strong median ridge, in lateral view gonocoxa elongate–rectangular, without projections; gonostylus normal, narrowly rounded apically; lateral ramus narrow, pointed apically, shorter than gonostylus; dorsolateral ramus straight, thick, rounded apically.

Female. As in male except as follows: Eyes separated at vertex by twice width of ocellar tubercle; front white pilose and tomentose, tomentum dense along eye margin; upper half of occiput, mesonotum, scutellum, and abdominal dorsum with abundant pale yellow tomentum. Genitalia with posterior projection of tergite VIII testaceous; vaginal furca ( Fig. 14 ) with upper half narrowly V­shaped; lower half with struts heavily chitinized, somewhat twisted medially, small inward projecting swelling on inner margin near apex; apex subrectangular.

Types. Holotype male and allotype (Mercury, Nye County, Nevada, 4.v.1961, BYU code 12m). Paratypes. United States: Nevada. Nye County: 63, topotypic, collected from May to September 1961. Utah. Juab County: 42, 14 mi. E. Eureka, 1.ix.1965 (R.H. & E.M. Painter); Millard County: 1, 46 mi. NW Delta, 4.ix.1965 (R.H. & E.M. Painter). Arizona. Yuma County: 1, 28 mi. N Yuma, 17.x.1979 (J.C. & E.M. Hall). California. San Bernardino County: 1, Joshua Tree National Monument, 10.v.1946 (A.L. Melander); 1, same data, 25.v.1982 (J.C. Hall). Mexico: Morelos. 1, 12 mi. E Cuernavaca, 13.iv.1966 (R.H. & E.M. Painter). Holotype and allotype deposited in USNM. Paratypes deposited in USNM and UCR.

Variation. With the usual variations of color intensity of the tomentum. The mid and hind tibiae may be darker than described.

Discussion. The female vaginal furca resembles somewhat that found in G. borealis , sp. nov., except that the struts on the lower half are more heavily chitinized and are not as conspicuously twisted.

Biology. Immature stages and adult flower preferences unknown.

Distribution. United States (Arizona, California, Nevada, Utah); Mexico (Morelos).

Etymology. The specific epithet refers to the type series being found in Nevada.

Figures

FIGURES 42 – 45. Geron male genitalia. 42, G. johnsoni Painter; a, lateral view; b, tip of gonocoxa, ventral view. 43, G. monticola Hall & Evenhuis, sp. nov.; a, lateral view; b, gonocoxa, dorsal view. 44, G. nevadensis Hall & Evenhuis, sp. nov.; a, lateral view; b, tip of gonocoxa, dorsal view. 45, G. nigripes Painter; a, lateral view; b, gonocoxa, ventral view.

FIGURES 13 – 18. Geron vaginal furcae. 13, G. monticola Hall & Evenhuis, sp. nov. 14, G. nevadensis Hall & Evenhuis, sp. nov. 15, G. nigripes Painter. 16, G. notios Hall & Evenhuis, sp. nov. 17, G. painteri Hall Evenhuis, sp. nov. 18, G. parvidus Painter.