Geron arenicola Painter

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 : 19-20

Geron arenicola Painter

Geron arenicolus Painter, 1932: 145 , 146, 160.

Geron arenicola Painter. Painter & Painter 1965: 423 (emendation). Hull 1973: 206. Evenhuis

1983: 463. Poole & Gentili 1996: 70. Evenhuis & Greathead, 1999: 37.

Description. Male. Head. Front with silvery white tomentum, pile wanting; antenna black; scape with white hair; pedicel with short black or dark brown hair; first flagellomere linear, tapering from broad base to acuminate apex; antennal ratio: 13:5:30; face cinereous pollinose, white pilose, bare medially, silver white tomentum laterally next to eye margin oral margin pale; proboscis projects beyond oral margin for a distance equal to one and one­half times head height; gena white pilose and tomentose; occiput white pilose, white tomentum on lower two­thirds laterally; ocellar tubercle with white hair.

Thorax. Mesonotum velvety black, cinereous pollinose laterally; median longitudinal pollinose stripe short, broad, not reaching transverse suture; notum white pilose with shorter black hair medially on posterior half; tomentum white to pale yellow, sparse; pleura white pilose and tomentose; legs black, mid and hind tibiae and hind basitarsus ferruginous, legs with white hair and scales; halter with stem and knob whitish; scutellum white to pale yellow pilose, tomentum (when present) pale yellow and located on side at base.

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

Abdomen. Dorsum white pilose and tomentose, tomentum scattered, tergites with lateral margins pale; sternites white pilose and tomentose, posterior margins narrowly pale.

Genitalia ( Fig. 32 ) with gonocoxa in ventral view somewhat broadened medially, flat, without depressions or ridges; gonocoxa in lateral view boat­shaped, ventral margin without projection; gonostylus short, broad, about two and one­half times longer than high, rounded apically; lateral ramus slightly curved, coextensive with gonostylus, rounded apically; dorsolateral ramus large, broad, nearly straight; aedeagus short, not readily evident.

Female. As in male except as follows: Head. Eyes at vertex separated by two times width of ocellar tubercle; front with white hair and golden yellow tomentum; occipital pile and tomentum on upper half white with yellowish cast. Thorax. Mesonotum white pilose and golden yellow tomentose; median longitudinal cinereous stripe broad, not reaching transverse suture. Abdomen. Dorsum white pilose, golden yellow tomentose, the latter abundant. Genitalia with posterior lobe of tergite VIII testaceous; vaginal furca ( Fig. 3 ) somewhat complicated, upper half broadly V­shaped; lower half with arms gently curved and with a median, apically acute, projection; apex of lower half with a kidney­shaped lobe.

Types. Holotype male and allotype (Dickinson County, Kansas, 24.ix.1924, R.H. Painter) in USNM (No. 44865). The genitalia of the holotype has been dissected and placed in a microvial attached to the pin. Both the holotype and the allotype are in good condition, at most only slightly rubbed. Studied by both authors during this study.

Material Examined. United States. Arizona. Cochise County: 1, Portal, 16.viii.1958 (C.G. Moore); 1, same data, 26.viii.1979 (S.I. & S.L. Frommer) ( UCR). Colorado. Powers County: 1, 5 mi. N. Holly, 7.viii.1963 (N. & B. Marston) ( USNM). La Plata County: 1, 2 mi. S Hesperus, 21.viii.1963 (N. & B. Marston) ( USNM). Grande County: 1, 7 mi. NW Alamosa, 28.viii.1963 (N. & B. Marston) ( USNM). Archuleta County: 1, 10 mi. E Pazosa Sprgs., 28.viii.1963 (N. & B. Marston) ( USNM). Saguache County: 1, nr. Saguache, 7.viii.1937 (R.H. Painter ( USNM). Los Animas County: 1, 23.viii.1963 (R.H. & E.M. Painter) ( USNM). Nevada. Lander County: 1, Austin Summit, 7.ix.1953 (K.W. Tucker) ( UCR). New Mexico. Otero County: 1, White Sand Natl. Mon. 17.viii.1962 (H.V. Weems, Jr.); 1, same data, 21.viii.1962 (H.V. Weems, Jr.) ( FSCA).

Variation. The color of the pile varies from white to pale yellow; the tomentum may be golden or dark yellow. The gonostylus in the holotype is triangular in lateral view, however, conspecific specimens show a more normally shaped gonostylus.

Discussion. In the original description it is stated that “basistylus with slight central ridge”. What appears to be a ridge in the specimens examined is actually a narrow depression. The characteristic shape of the vaginal furca easily distinguishes the females.

Biology. Immature stages and adult flower preferences unknown.

Distribution. United States (Arizona, Colorado, Kansas, Massachusetts, Minnesota, Nebraska, New Mexico, New York, Utah).

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.