Geron infrequens 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 : 35-36

Geron infrequens Hall & Evenhuis , sp. nov.

Male. Head. Front with silvery white tomentum, hair wanting; antenna black; scape with white hair; pedicel with short black hair; first flagellomere evenly tapering from base to acuminate apex; antennal ratio: 10:4:26; face cinereous pollinose, white pilose, bare medially; silver­white scales lateral of antennal base; oral margin 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, pale yellow hair and no scales on upper half; ocellar tubercle with brown to black hair.

Thorax. Mesonotum dull black, lateral margin lightly cinereous pollinose; median longitudinal stripe vague, short, not reaching half­way to transverse suture; notum white pilose with shorter black hair medially behind transverse suture; with scattered golden yellow tomentum; pleura white pilose and tomentose; legs black with white hair and scales; halter with stem and knob pale yellowish; scutellum white pilose, tomentum wanting.

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

Abdomen. White pilose, tomentum on dorsum golden yellow, scattered; white tomentum on side and venter; tergites with lateral margins narrowly pale; sternites with posterior margins narrowly pale.

Genitalia ( Fig. 41 ) with gonocoxa in ventral view flat, without depressions or ridges, in lateral view, narrowly elongate, lower margin with a small, rounded projection; gonostylus normal, about three times longer than high, rounded apically; lateral ramus narrow, straight, shorter than gonostylus; dorsolateral ramus very short, stubby, rounded apically.

Females. As in male except as follows: Head. Eyes at vertex separated by 1.75 times width of ocellar tubercle; front cinereous pollinose, with white hair; tomentum golden yellow medially, white laterally and above antenna; pedicel with short white hair; occiput with yellow tomentum on upper half. Thorax. Mesonotum with median longitudinal stripe long, undivided, nearly reaching base of scutellum; notum and scutellum with yellow tomentum. Abdomen. Dorsum with abundant yellow tomentum. Genitalia with posterior lobe on tergite VIII black; vaginal furca ( Fig. 12 ) simple; upper half V­shaped, lower half with arms curved, bluntly swollen apically with an upward and inward projecting spur.

Types. Holotype male and allotype (Three Pines Canyon, Walker Pass, Kern County, California, 9.vii.1987, J.C. Hall & N.L. Evenhuis, on Heliotropium curassavicum ). Paratypes. California. 3, topotypic, collected with types; Kern County: 3, Walker Pass, 19.viii.1958, 8.x.1957, 23.ix.1981 (R.H. & E.M. Painter, P.H. Timberlake, J.C. Hall); 2, Cane Brake Creek, Walker Pass, 9.vii.1987 (N.L. Evenhuis); San Diego County: 6, Julian, 20.vii.1982 (J.C. Hall); Tuolumne County: 1, Buck Meadows, 17.vii.1958 (J.C. & E.M. Hall). Holotype and allotype deposited in USNM. Paratypes deposited in USNM, BPBM, and UCR.

Variation. The usual color variations have been noted. The tomentum on the dorsum of the females varies from yellow to golden yellow. Not all males have apparent black hair on the second antennal segment. On occasion the mid and hind tibiae are light in color.

Discussion. The males of G. infrequens are similar to some specimens of G. nigripes . The two species can be separated by the much shorter projection on the venter of the gonocoxa of G. infrequens . The vaginal furca in the female is similar to that found in G. subauratus ; however, the inward projections on the lower half of the apodeme are shaped differently (cf. Figs. 12 and 24 ).

Biology. Immature stages unknown. Adults have been taken at flowers of Heliotropium curvassavicum .

Distribution. United States (California).

Etymology. The specific epithet derives from the Latin “ infrequens ” = seldom, rare; referring to the relative rarity of specimens of this species in collections.

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.

FIGURES 19 – 24. Geron vaginal furcae. 19, G. peucon Hall & Evenhuis, sp. nov. 20, G. prosopidis Hall & Evenhuis, sp. nov. 21, G. rufipes Macquart. 22, G. senilis (Fabricius. 23, G. stenos Hall & Evenhuis, sp. nov. 24, G. subauratus Loew.