Geron albidipennis Loew

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 : 14-17

Geron albidipennis Loew

Geron albidipennis Loew, 1870: 174 (1872: 212) . Osten Sacken 1877: 265. Osten Sacken 1878: 41. Johnson 1894: 275. Aldrich 1905: 245. Painter 1932: 167. Painter & Painter 1965: 422. Hull 1973: 206. Evenhuis 1982: 3. Evenhuis 1983: 462. Poole & Gentili 1996: 70. Evenhuis & Greathead 1999: 37.

Description. Male. Head. Frontal triangle silvery white tomentose, pile wanting; antenna with white hair; first flagellomere narrow, tapering from base to acuminate apex; antennal ratio 8:3:21; face cinereous pollinose, white pilose, bare medially, tomentum at side silvery white; oral margin pale; proboscis projects beyond oral margin for a distance equal to about two times head height; gena cinereous pollinose with white hair and scales; occiput white pilose, lower half with white scales; vertex and ocellar tubercle with brownish hair.

Thorax. Mesonotum velvety black, side cinereous pollinose; median longitudinal cinereous stripe not evident, notum white pilose, short black hair medially behind transverse suture, tomentum golden yellow, scattered; pleura cinereous pollinose, white pilose; legs black, tibiae ferruginous, white pilose and tomentose; halter with stem and knob yellowish; scutellum with white hair, tomentum wanting.

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

Abdomen. Dorsum white pilose, golden yellow tomentose; side and venter white pilose and tomentose; tergites with lateral margin pale; sternites with posterior margins pale.

Genitalia ( Fig. 30 ) with gonocoxa in ventral view with two deep pits and a prominent central ridge separating them; gonocoxa in lateral view narrow, more than two times longer than high, lower margin undulate medially, without projections; gonostylus narrow, rounded apically; lateral ramus narrow, slightly curved, pointed apically, coextensive with gonostylus; dorsolateral ramus large, prominent, slightly curved downward; aedeagus not prominent.

Female. As in male except as follows: Head. Eyes separated at vertex by slightly more than one and one­half times width of ocellar tubercle; front with white hair and silverwhite tomentum; occiput with pale yellow scales on upper half; vertex and ocellar tubercle with pale yellow hair. Thorax. Mesonotum with median longitudinal cinereous stripe narrow, not divided, nearly reaching scutellum, notum with white pile anteriorly, shorter golden yellow pile posteriorly, tomentum pale yellow to golden yellow, abundant; fore tarsi with palynophilic setae. Abdomen. Dorsum white pilose, tomentum yellow to golden yellow, abundant. Genitalia with posterior projection of tergite VIII rounded, black; vaginal furca ( Fig. 1 ) with upper half V­shaped, lower half stout, subtriangular lateral arms thick, tapering from bilobed broad base to narrowed apex, without internal rami.

Types. Holotype male (“Cala.” [= California]) deposited in MCZ (No. 12713). The type has apparently been in alcohol; the head is shrunken, only a small piece of the right wing is remaining, middle left leg and the right antenna are missing. The genitalia have been dissected and placed in a microvial, attached to the pin below the labels. Loew (1870) gave Agassiz as the collector, but there is nothing on the label to indicate Agassiz as the collector. The top label says “Cala”. Type studied by both authors during this study.

Material Examined. United States: Arizona. Maricopa County : 14, 18 mi. E Gila Bend, 16.x.1979 (J.C. & E.M. Hall); 2, 4 mi. N Stonecabin, 17.x.1979 (J.C. & E.M. Hall) ( UCR). Cochise County: 1, Portal, Chiracahua Mts, 15.viii.1958 (R.M. Bohart) ( UCR); 1, Fort Huachuca, 5.v.1948 (A.L. Melander ( USNM); Gila County: 1, 11.1 Mi. S Seneca, 24.viii.1964 (E.I. Schlinger) ( UCR); 1, 48 mi. NE Globe, 19.vi.1961 (R.H. & E.M. Painter) ( USNM). Pinal County: 1, 4 mi. E Oracle, 9.vi.1961 (R.H. & E.M. Painter ( USNM). Santa Cruz County: 1, Lochiel, 1.ix.1958, (R.H. & E.M. Painter) ( USNM). California: Imperial County: 11, 3.5 mi. NW Glamis, Algodones dunes, 13.iv.1968 (R. Hobza, P. Rauch, Devol, C. Beesley, E.I. Schlinger) ( UCR). San Bernardino County: 2, Granite Pass, 27.iv.1968 (R. Hobza) ( UCR); 1, Joshua Tree, 8.vi.1965 (M.W. Stone) ( UCR). San Diego County: 10, June Wash, 5.xi.1984 (J.C. Hall) ( UCR). New Mexico. Hidalgo County: 1, Post Office Canyon, 9.viii.1965 (G.R. Ballmer) ( UCR). Texas. Brewster County: 1, 40 mi. S Alpine, 18.vi.1958 (R.H. Painter) ( USNM). Brown County: 1, Brownwood, 8.ix.1922 ( USNM). Mason County: 1, Mason, 24.viii.1926 [no collector given] ( USNM). Utah. Millard County: 1, Delta, 20.viii.1957 (E.M. & R.H. Painter) ( USNM). Mexico. Baja California Norte: 3, 19 mi. N. San Felipe, 10.iv.1968, 1, same data, 11.iv.1968 (M.E. Irwin) ( UCR). Sonora: 2, 13 mi. S. Hermosillo, 28.i.1964 (P.A. Rauch) ( UCR), 3, 41 mi. S. Santa Ana, 19.vi.1968 (J. Smith, M. Wargo), 1, 37 mi. S. Santa Ana (R.H. & E.M. Painter) ( USNM). Chihuahua: 1, 15 mi. S. Camargo, 6.ix.1962 (R.H. & E.M. Painter) ( USNM); 1, 24 mi. SW Chihuahua, 6.ix.1962 (R.H. & E.M. Painter) ( USNM). Nuevo León: 1, 16 mi. N. Vallecillo, 6.viii.1968 (R.H. & E.M. Painter) ( USNM). Durango: 1, 64 mi. S. La Zarca, 5.ix.1962 (R.H. & E.M. Painter) ( USNM).

Variation. With the usual variations of pile color (white to pale yellow) and tomentum color (yellow to golden yellow). In some females the hair on the ocellar tubercle is brown or black. Males from Texas and some areas of Mexico have the gonocoxa flat with only a slight indication of depression or a separating ridge.

Discussion. As mentioned under G. senilis , the two species are similar. The major difference lies in the male and female genitalia. In most G. albidipennis males the two pits and the median ridge on the venter of the gonocoxa are very prominent; in the females the lower half of the vaginal furca is much stouter and the apical lobes are less pronounced than in G. senilis (cf. Figs. 1 and 22 ).

Biology. Immature stages unknown. Adults have been taken at flowers of Euphorbia hypericifolia , Gutierrezia sp., Haplopappus sp., Hymenothrix sp. and Grindellia sp.

Distribution. United States (Arizona, California, New Mexico, Texas, Utah); Mexico (Baja California Norte, Chihuahua, Durango, Nuevo León, Sonora).

Figures

FIGURES 30 ­ 33. Geron male genitalia. 30, G. albipennis Painter; a, lateral view; b, tip of gonocoxa, ventral view. 31, G. albipilosus Hall & Evenhuis, sp. nov.; a, lateral view; b, ventral view. 32, G. arenicola Painter; a, lateral view; b, tip of gonocoxa, ventral view. 33, G. argutus Painter; a, lateral view; b, ventral view.

FIGURES 1 – 6. Geron vaginal furcae. 1, G. albidipennis Loew. 2, G. albipilosus Hall & Evenhuis, sp. nov. 3, G. arenicola Painter. 4, G. argutus Painter. 5, G. borealis Hall & Evenhuis, sp. nov. 6, G. confusus 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.