50 Annals Entomological Society of America [Vol. VI, 



Note. — Under tenuis I have given the characters that sep- 

 arate the males of these two species ; the females of these species 

 can be distinguished from those of tenuis in having only the 

 humeri yellow, the pleurae being altogether black, and the 

 dorsum dull greenish, while in tenuis there is more or less 

 yellow on the dorsum and pleurae. 



21 Neurigona aestiva n. sp. 



Figure 21. 



Thorax blackish; abdomen yellow with black bands; hypopygium 

 black with the upper part more or less yellow; front tarsi plane. Length 

 b}4 mm. 



Male: Face narrow, of nearly equal width throughout, face and 

 palpi silvery white; proboscis and antenna yellow, the latter with the 

 third joint very small; arista brown; front and occiput blackish, but 

 the ground color concealed by white pollen; orbital cilia whitish; post- 

 vertical bristles yellow. Thorax and metanotum blackish with white 

 pollen, shining on the dorsum, pollen thickest on the pleuree and the 

 flattened space before the scutellum; humeri, a large spot at the inser- 

 tion of the wings, and the scutellum except the base yellow; meta- 

 thoracic epimera yellowish white; most of the bristles of the dorsum 

 small and weak, the acrostichal bristles can hardly be traced in some 

 individuals, but in others they are distinct. Abdomen yellow, the first 

 segment more whitish; second segment with a black band near the base; 

 third with a black band at the base ; fourth black at base getting paler 

 posteriorly; fifth segment dusky yellow, with the ventral sheath large 

 and black; hairs of the abdomen and the bristles on the hind margin of 

 the first segment yellow, those on the lower part of the fourth segment 

 long; hypopygium mostly black or testaceous, shining, sometimes the 

 first half parti}' yellowish. Legs yellowish white; hind femora more 

 yellowish; hairs and bristles of the front coxae all whitish, those of the 

 middle coxa? black; front tarsi more than twice as long as their tibiae, 

 their metatarsi hardly as long as the tibiae, and about equal to the 

 second and third joints taken together; middle metatarsi four-fifths as 

 long as their tibiae; second joint of the hind tarsi longer than the first; 

 all the tarsi slightly darker towards the tip. Wings hyaline, slightly 

 tinged with yellowish along the front; third and fourth veins quite 

 widely separated at the tips ; fourth vein ending in the apex of the wing. 



Described from three males from N. Y., Md., and Vt. I 

 took the type specimen at Lancaster, N. Y., June 2, 1912; 

 Prof. C. W. Johnson has sent me one which was taken at Nor- 

 wich, Vt., July 7, 1908; and there is one in the National Museum 

 collection taken on Plummers Island, Md., May 11, 1905, by 

 Mr. Schwarz. 



