18 PROCEEDINGS OP THE NATIONAL MUSEUM vol. 66 



12. ARGYRA ROBUSTA Johnson 



Argyra roiusta Johnson, Psyche, vol. 13, p. 59, June, 1906. 



Male. — Length, C-7 mm. Face wide; silveiy white. Palpi black, 

 with black hairs. Front covered with white pollen. Antennae black ; 

 first joint with stiff hairs above; third joint about twice as long as 

 Tvide; arista siibapical, as long as the antenna. Beard grayish- 

 white, abundant. 



Thorax dark green with considerable grayish-white pollen ; scutel- 

 lum with many long, black hairs on the disk and four large, marginal 

 bristles. Abdomen black, second and third segments with large 

 yellow spots on the sides, those on second only leave a narrow black 

 margin on anterior and posterior edges and a wide median stripe. 

 Abdomen covered with silvery white pollen, all its hairs black. 

 Hypopygial lamellae rather narrow and curved, yellow at base, more 

 or less black at tip, fringed with black hairs; back of these is a long 

 yellowish portion of the hypopygium. 



All coxae black with black hair and bristles. All femora black 

 with their tips narrowly yellow, anterior pair with long black hair 

 on the posterior surface; middle pair with moderately long hair 

 below ; posterior pair with several bristlelike hairs near the tip. All 

 tibiae yellow, extreme tips of hind pair brownish. Fore and middle 

 tarsi infuscated from the tip of the first joint, still the other joints 

 paler at base ; hind tarsi black with the first joint yellowish at base. 

 Joints of fore tarsi as 50-17-15-8-10; first joint with conspicuous 

 bristles below, which are as long as the diameter of the joint; middle 

 tarsi with the joints as 62-24r-19-10-12 ; those of hind tarsi as 

 49-35-27-20-14. Calypters white with a black border and yellowish 

 cilia. Halteres yellow. 



Wings grayish, slightly tinged with brown in front and along the 

 veins; third vein bent back at tip; last section of fourth vein bent 

 at its middle, parallel with third at tip ; last section of fifth vein one 

 and a half times as long as the cross vein. 



Female. — Differs from the male in having the pollen of the thorax 

 and abdomen more brownish ; the face wide and more gray, or gray- 

 ish-yellow; its suture far below the middle, sinuous; lower edge 

 of the face rounded; third antennal joint about as long as wide, 

 arista apical. Fore and middle femora more or less blackened at 

 base, sometimes largely black, their hair shorter than in the male; 

 hind femora wholly yellow. All tibiae yellow. Hind tarsi usually 

 wholly black; still sometimes the first joint is yellow with a black 

 tip. 



This species differs from albiventris Loew chiefly in having hair 

 on the scutellum and in the proportionate length of the joints of 

 the tarsi and the bristles on the lower surface of the fore tarsi; in 



