Geron halli 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 : 32-33

Geron halli Evenhuis , sp. nov.

Male. Head. Front with sparse silvery white tomentum, hair wanting; antenna black; scape with brownish black hair; pedicel with short black hair; first flagellomere evenly tapering from base to acuminate apex; antennal ratio: 10:4:26; face cinereous pollinose, silvery white pilose, bare medially; silver­white hair lateral to antennal base; oral margin grayish white; proboscis projects beyond oral margin for a distance about one and one­half times head height; gena white pilose and tomentose; occiput with white hair and scales on lower half, yellow hair and no scales on upper half; ocellar tubercle with yellowish hair.

Thorax. Mesonotum dull black, lateral margin lightly brownish to cinereous pollinose; median longitudinal stripe absent; notum white pilose with shorter and sparser hair behind transverse suture, scattered golden yellow tomentum; pleura white pilose and tomentose; katepisternum sparsely white pilose; femora and tarsi black, tibiae brown, all with white hair and scales; halter with stem and knob yellowish; scutellum yellowish pilose, tomentum wanting.

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

Abdomen. Black above, cinereous pollinose below, brownish gray on sides; white pilose, tomentum on dorsum golden yellow, scattered; white tomentum on side and venter.

Genitalia ( Fig. 39 ) with gonocoxa in ventral view broad, without distinctive depressions or ridges, basally with distinctive large lateral flap­like projections; in lateral view, broadly elongate; gonostylus normal, about three times longer than high, slightly rounded apically; lateral ramus narrow, straight, subequal in length to gonostylus; dorsolateral ramus very short, stubby, apically rounded.

Female. As in male except as follows: Head. Eyes at vertex separated by 1.75 times width of ocellar tubercle; front cinereous pollinose along inner eye margin, with white hair, dull black medially with yellow hairs, tomentum golden yellow medially, white laterally and above antenna; scape and pedicel with short white hair; occiput with golden yellow tomentum on upper half. Thorax. Mesonotum with median longitudinal stripe nearly reaching transverse suture; notum and scutellum with yellow tomentum; pleura with meron bare; legs brown, femora and tibiae cinereous pollinose; fore tarsi with palynophilic setae. Abdomen. Dorsum with abundant yellow tomentum. Genitalia with posterior lobe on tergite VIII black; vaginal furca ( Fig. 10 ) simple; upper half narrowly V­shaped, lower half with arms curved, bluntly swollen basally with an upward and inward projecting spur.

Types. Holotype male and allotype (5 mi. E Seneca, Nemaha County, Missouri, 4.vi.1963, N. & B. Marston). Paratypes. 5, topotypic, collected with the types. Holotype, allotype, and paratypes deposited in USNM.

Variation. The short type series shows no appreciable variation in the characters given above.

Discussion. The males of G. halli are similar to some specimens of G. peucon , sp. nov. and can be separated from it by the sparse white pilose katepisternum (this pleuron dense white pilose in G. peucon ) and the distinctive shape of the gonocoxa (fig. 39); the females can be separated from G. peucon , sp. nov. by the bare meron (pilose in G. peucon ) and the distinctive shape of the vaginal furca ( Fig. 10 ).

Biology. Immature stages and adult flower preferences unknown.

Distribution. United States (Missouri).

Etymology. Named for Jack Clayton Hall (1925–) who has encouraged the junior author to work diligently on Bombyliidae , even after the senior author’s premature retirement in 1988 from the University of California at Riverside. Jack began the work on this revision and his sudden retirement forced him to abort a nearly finished study of this subgenus of Bombyliidae . It is the pleasure of the junior author to belatedly complete this study and honor him with a patronymic species that was not a part of his original revisionary notes on the subgenus.

Figures

FIGURES 38 – 41. Geron male genitalia. 38, G. eriogonae Hall & Evenhuis, sp. nov.; a, lateral view; b, tip of gonocoxa, ventral view. 39, G. halli Evenhuis, sp. nov.; a, lateral view; b, gonocoxa, ventral view. 40, G. holosericeus Walker; a, lateral view; b, tip of gonocoxa, ventral view. 41, G. infrequens Hall & Evenhuis, sp. nov.; a, lateral view; b, gonocoxa, dorsal view, epiphallus and phallic complex removed.

FIGURES 7 – 12. Geron vaginal furcae. 7, G. cressoni Hall & Evenhuis, sp. nov. 8, G. elachys Hall & Evenhuis, sp. nov. 9, G. eriogonae Hall & Evenhuis, sp. nov. 10, G. halli Evenhuis, sp. nov. 11, G. holosericeus Walker. 12, G. infrequens Hall & Evenhuis, sp. nov.