8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 66 



Thorax green on the dorsum, its posterior portion and the scutel- 

 him with deep bhie reflections, the latter Avith two pairs of marginal 

 bristles, its disk bare; the pollen on the dorsum of the thorax gray 

 and confined to the anterior portion ; pleurae black with white pollen. 

 Abdomen Avholly green, with coppery reflections and white pollen, 

 which is not silvery. Hypopygium and its appendages (fig. 4) 

 black; outer lamellae rounded at apex and slightl}^ clubbed; inner 

 appendages small. 



All coxae and femora black ; fore and middle coxae with stiff black 

 hair. Posterior surface of fore femora and lower anterior surface 

 of middle ones with abundant black hair, which is as long as the 

 width of the femora. Fore and middle tibiae yellow^, the former 

 Avith two rows of rather long slender bristles, otherwise with only 

 short hair; middle ones with two rows of bristles above and several 

 smaller ones below. Hind tibiae wholly black, with a row of five 

 moderately long bristles on upper outer edge. Fore and middle tarsi 

 blackish, a little longer than their tibiae; fore tarsi with its joints 

 as 36-9-7-5-7, the first joint W'ith the hairs on its lower edge as lon^ 

 as its diameter. Middle tarsi with the first joint as long 

 as the remaining four taken together; fourth and fifth of equal 

 length. Hind tarsi wholly black, the joints as 40-26-17-12-10, the 

 first joint a little arched. Calypters brown with black tips and cilia ; 

 halteres yellow. 



Wings a little tinged with brown; third vein only a little bent 

 back at its tip ; last section of fourth vein bent at its middle, parallel 

 with third beyond this bend, ending in the apex of the wing; last 

 section of fifth vein about twice as long as the crossvein. 



Described from one male taken by Dr. J. M. Aldrieh at Tennessee 

 Pass, Colorado, July 24, 1917. 



Type.— Male, Cat. No. 27034, U.S.N.M. 



This differs from both nigripes Loew and barhipes, new species, in 

 having the hypopygial lamellae broadly rounded at tip, the third 

 antennal joint shorter and in the proportional length of the joints of 

 fore and hind tarsi. 



3. ARGYRA CYLINDRICA Loew 



Argijra cylimlrica Loew, Smiths. Misc. Coll., No. 171, p. 132, 1864. 



Male. — Length, 4.5 mm. Face moderately wide, silvery white. 

 Front green with white pollen: palpi and proboscis black. Antennae 

 (fig. 2) black; first joint with four stiff' hairs above; third joint 

 scarcely longer than the two basal joints together ; arista fully three 

 times as long as the antenna. Lower orbital cilia and the beard 

 sordid white; the small black upper cilia reach down nearly to the 

 middle of the eye. 



