6 PEOCEEDIXGS OF THE NATIONAL MUSEUM. vol. 61. 



it is separable by many characters, among them the infiiscation in the 

 wing tip. 



Male. — Front green. Face pale yellow, rather narrow. Palpi 

 black. Antennae entirely black, rather short. Orbital cilia entirely 

 black. 



Mesonotum and scutellimi rather obscure green, with coppery reflec- 

 tions and rather distinct changeable stripes. Pleurae blackish green, 

 but little shining. Cilia of calypters white. Halteres yellow. Abdo- 

 men rather long, dark green. Hj^popygium large, the lamellae white, 

 rather square across the apical end where they are broadly bordered 

 with black, deeply notched and provided with the usual curved bris- 

 tles ; the upper border is fringed with erect hairs which become larger 

 toward the base. 



Coxae black, the front ones somewhat silvery on the anterior side, 

 with small dark hairs. Femora black except the extreme knees; 

 front tibiae yellow, the middle tibiae yellow but on the outer side 

 distinctly white and without the usual small black hairs. The tip 

 of the middle tibia distinctly infuscated, hind tibia yellow, slightly 

 darkened at base, with the apical fifth black. Front tarsi plain, the 

 first joint yellow except at extreme tip, the remainder black; middle 

 tarsus with the first joint brown, its apical fourth white, on the outer 

 side snow-white and bare, the extreme tip and all the following joints 

 deep black; hind tarsi deep black, the first joint as long as all the 

 following and bearing about 14 bristles in several erect rows, one of 

 which is on the under side; the middle femora have a row of short 

 white cilia beginning about the middle, the hind femora with a row 

 of long white cilia from the middle. 



Wings elongate, rather narrow, with a uniform gray tinge and a 

 distinct apical dark spot, which begins at about the tip of the second 

 vein and extends almost to the hind margin, filling out the apex 

 except a narrow border beginning behind the tip of the fourth vein ; 

 hind cross vein bearing a slight cloud ; anal angle small, costa with a 

 distinct thickening at the end of the first vein. 



Female. — Face a little wider than the male ; front coxae with many 

 more black hairs. Cilia of calypters yellow, middle tibiae not quite 

 so wide as in the male, the middle basitarsus brown, its extreme tip 

 black. Wing broader than in the male, the apical spot present, but 

 less distinctly defined; hind cross vein very distinctly infuscated. 



Length of male 6.2 mm. ; of female 5.8 mm. 



The only species known in North America which is at all similar 

 to this one is aiinulipes Zetter.stedt {stenhammari of authors), Avhich 

 also has black legs with the middle tibiae and tarsi ornamented with 

 white. It, however, has a different color pattern and is easily sepa- 

 rable by having black cilia on the calypters. 



