Geron holosericeus Walker

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 : 33-35

Geron holosericeus Walker

Geron holosericeus Walker, 1849: 295 . Osten Sacken 1858: 43. Osten Sacken 1878: 94. Aldrich 1905: 245. Kertész 1909: 98. Painter 1932: 166. Painter & Painter 1962: 47; 1965: 423. Cole & Schlinger 1969: 234. Miller & Kurczewski 1976: 275. Painter, Painter & Hall 1978: 17. Poole & Gentili 1996: 71. Evenhuis & Greathead 1999: 42.

Geron digitaria var. robustus Cresson, 1919: 185 .

Geron niveoides Cole, 1923: 312 . Hull 1973: 206. Arnaud 1979: 212. Hull 1973: 206. Cole & Schlinger 1969: 234. Painter, Painter & Hall 1978: 17. Evenhuis, 1983: 475.

Geron insularis Cole, 1923: 313 . Painter, Painter & Hall 1978: 17. Arnaud 1979: 212. [Preoccupied by Bigot, 1857.]

Geron versicolor Painter, 1932: 145 , 156. Brimley 1938: 342. Byers et al. 1962: 143. Painter & Painter 1962: 47. Painter & Painter 1965: 423. Poole & Gentili 1996: 71. Evenhuis & Greathead 1999: 42.

Geron robustus Cresson. Painter & Painter 1965: 423 . Evenhuis 1983: 487. Poole & Gentili 1996: 71.

Geron colei Hull, 1973: 206 , 665. Nomen nudum.

Geron colei Painter, Painter & Hall 1978 [20 April]: 17 (n.n. for insularis Cole ).

Geron colei Evenhuis, 1978 [30 November]: 247 (n.n. for insularis Cole ).

Geron saxosus Tabet, 1979: 184 . Nomen nudum.

Geron saxosus Tabet, 2001: 51 . Syn. nov.

Description. Male. Head. Front silver white tomentose, pile wanting; antenna black; basal segments with white hair, pedicel with a few short black hairs apically; first flagellomere linear, tapering evenly from broad base to acuminate apex; antennal ratio: 12:5:30; face cinereous pollinose, pale testaceous at tip of oral margin, with white hair, bare medially, tomentum silver white, restricted to side next to eye margin; oral margin dark (cinereous pollinose thus appearing pale in some light); proboscis projects beyond oral margin for distance equal to twice head height; gena white pilose and tomentose; occiput white pilose, hair at vertex yellowish, tomentum on lower half silvery white; ocellar tubercle with white hair.

Thorax. Mesonotum dull black, lateral and anterior margins cinereous pollinose; median longitudinal cinereous stripe short, divided, not reaching transverse suture; notum white pilose, dark hair medially on posterior half, tomentum pale yellow, scattered, primarily above and behind root of wing; scutellum white pilose, tomentum wanting; pleura white pilose and tomentose; legs black, mid and hind tibiae and basitarsi ferruginous, white pilose and tomentose, fore and hind femora with some orange scales dorsally at apex; halter with stem and knob whitish.

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

Abdomen. Dorsum white to pale yellow pilose, white to pale yellow tomentose, scales not abundant; side and venter white pilose and tomentose, scales somewhat silvery; tergites with lateral margins narrowly pale; sternites with posterior margins narrowly pale.

Genitalia ( Fig. 40 ) with gonocoxa in ventral view flat, without depressions or ridges, in lateral view, boat­shaped, lower margin without projections; gonostylus large, broad, rounded apically; lateral ramus narrow, nearly coextensive with gonostylus, narrowly rounded apically; dorsolateral ramus broad, approximately half length of lateral ramus; aedeagus not evident.

Female. As in male except as follows: Head. Eyes at vertex separated by slightly more than one and one­half times width of ocellar tubercle; front with white hair and scales; ocellar tubercle with white hair. Thorax. Mesonotum white to pale yellow pilose and tomentose, the latter abundant; median longitudinal cinereous stripe vague; scutellum white to pale yellow pilose and tomentose, scales abundant; fore tarsi with palynophilic setae. Genitalia with posterior lobe of tergite VIII rounded, black; vaginal furca ( Fig. 11 ) large, simple; upper half V­shaped; lower half with arms stout, slightly bent, outer margin enlarged and pointed medially, arms basally narrowed and projecting downward, rounded apically.

Types. Lectotype male of G. holosericeus ( Georgia) in BMNH designated by Painter & Painter (1962: 47). Holotype female of G. digitaria var. robustus (Hancock, Maryland, 15.viii, F.R. Cole) in ANSP (No. 6208). Holotype male of G. niveoides (San Jose Island, Gulf of California, Mexico, 10.vi.1921, E.P. Van Duzee) in CAS (No. 1234). Holotype male of G. insularis Cole (Tiburon Island, Gulf of California, Mexico, 23.iv.1921, E.P. Van Duzee) in CAS (No. 1302). Holotype male of G. versicolor (Manhattan, Kansas, 6.ix.1926, R.H. Painter) in USNM (No. 44866). Holotype male of G. saxosus (Crater of the Moon Natl. Mon., Butte Co., Idaho, 16.viii.1964, D.S. Horning) in CAS (No. 14298). The male genitalia of all of the types have been dissected and placed in microvials attached to the pins. The senior author has studied all types above except G. saxosus . The holotype of G. saxosus has been studied by the junior author.

Material Examined. Hundreds of specimens from the following countries and states (asterisks indicate new distribution records): United States (Arizona, Colorado, New Mexico, Texas, Washington); El Salvador *, Mexico (Chihuahua, Coahuila, Colima*, Durango*, Guerrero, Jalisco, Michoacán, Morelos, Nayarít, Oaxaca, Puebla, San Luis Potosí, Sinaloa, Sonora, Tamaulipas, Veracruz); Nicaragua *.

Variation. The usual variations with regards to the color of the pile and tomentum have been noted. Not all specimens have the orange scales at the apices of the fore and hind femora. The second antennal segment may or may not have short black hair. In the females the posterior projection of tergite VIII is often longer and narrower than as described.

Discussion. A direct comparison of the characteristic genitalia of both sexes of all the named taxa in the synonymy list leaves little doubt as to the validity of the synonymy given above. This is one of the more easily recognized species of Geron . Males can be distinguished by the large gonostyli (evident even in the rosette condition); females can be distinguished by the characteristic shape of the vaginal furca ( Fig. 11 ).

Biology. Immature stages and adult flower preferences unknown.

Distribution. United States (Arizona, Colorado, Florida, Georgia, Illinois, Kansas, New Mexico, New Jersey, North Carolina, Oklahoma, Texas, Washington); Mexico (Baja California Sur, Chihuahua, Coahuila, Colima, Durango, Guerrero, Jalisco, Michoacán, Morelos, Nayarít, Nuevo León, Oaxaca, Puebla, San Luis Potosí, Sinaloa, Sonora, Tamaulipas, Veracruz, Yucatán); El Salvador; Guatemala; Nicaragua.

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.