36 INSECUTOR INSCITI^ MENSTRUUS 



sides of the dorsum. Pleurae shining black, a silvery band ex- 

 tending upward from sternopleura, across mesopleura, and 

 joining a large triangular patch on mesonotum just in front of 

 the transverse suture. Abdomen shining black, with black 

 hairs ; seventh segment silvery pollinose ; hypopygium small 

 but prominent. Front legs with the coxae bright yellow, elongate, 

 with a few black bristles distally, well separated ; trochanters 

 yellow ; femora yellow, somewhat darkened beyond basal third ; 

 tibiae and bases of the first tarsal joints yellow, the rest of 

 the tarsi darkened. Middle legs with the coxae blackish, 

 trochanters yellow, femora yellow, darkened at the middle ex- 

 teriorly; tibiae yellow, the tarsi wholly dark. Hind legs with 

 the coxae blackish, the trochanters yellow, femora yellow with 

 a darkened band about the middle ; tibiae slightly darkened ; 

 tarsi wholly dark, the first joint with a small tuft of yellow 

 bristles at the base on under side. On the hind legs the 

 trochanters and bases of the femora on the inner side each 

 bear a distinct row of small but stout black bristles. Wings 

 hyaline, the veins yellowish brown, the venation normal ; 

 fourth vein with the last section about twice the length of the 

 penultimate. Squamae yellowish, with very long white ciliation. 

 Halteres darkened at base, the knobs whitish, the dorsal mar- 

 gin of the stem with small black bristles. Length : Body about 

 7 mm., wing 7 mm. 



Great Falls, Virginia, July 30, 1913 (F. Knab) ; near Plum- 

 mer's Island, Maryland, May 37, 1915 (R. C. Shannon). 



Type, Cat. No. 30189, U. S. Nat. Mus. 



Described from two males. This species can be distinguished 

 at once from luteipennis and longimana by its larger size and 

 the bright yellow third antennal joint. The wings are less 

 broadly rounded apically and the alulae and anal lobes much 

 more developed. The ocellar bristles are very weak, as in 

 Hendel's genus Neotanypeza, while the postverticals are fairly 

 well developed. Some of our neotropical material shows inter- 

 mediate conditions in the development of these bristles. 



Date of publication, March 31, 1916. 



