560 TERTIARY IN^SECTS OF NORTH AMERICA. 



ill this connection until other material is at hand, while the species is 

 described wholly from the more perfect individual. This has a body more 

 nearly of the shape of an Orthoneura, the abdomen being broader and 

 stouter than is usual in Chilosia, but the wings are much longer than in the 

 species of Orthoneura I have seen, and both the shape of the wing and its 

 neuration agree well with Chilosia. The head is round and moderately 

 large, the thorax stout and rounded ovate, the scutellum large, semi-lunar, 

 twice as broad as long ; all these parts are dark brown. The wings are very 

 long and narrow, extending much beyond the tip of tlie abdomen, the costal 

 edge very straight until shortly before the tip, where it curves rapidly ; all 

 the veins are very straight, especially those of tlie upper half of the wing ; 

 the auxiliary vein terminates in the middle of the costal border, the first 

 longitudinal at the extremity of the straight part of the costa, beyond 

 the middle of the outer half of the wing, the third at the tip of the 

 wing, and the second midway between the first and third ; the third is 

 ixnited to the fourth by a straight cross-vein in the middle of the wing, 

 directly beneath the tip of the auxiliary vein, and about its own length 

 beyond the extremity of the long second basal cell ; the extremity of the 

 third basal cell is very oblique and reaches the tip of the lower branch of 

 the fifth longitudinal vein ; the marginal vein, uniting the third and fourth 

 veins, strikes the former just before the tip, while that uniting the fourth 

 and fifth, toward which the fourth bends to receive it, is removed farther 

 from the margin by about half the width of the first posterior cell. The legs 

 are slender, scantily clothed with short, fine hairs. The abdomen is broad, 

 oblong ovate, fully as broad as the thorax, broadly rounded at the apex, no 

 longer than the rest of the bodv, of a light color, with darker incisures, and 

 scantily covered with delicate hairs ; it is composed of five segments, of 

 which the second, third, and fourth are of equal length, the first shorter and 

 suddenly contracted, the apical nnnute. 



Length of body, 7"''" ; diameter of head, LSo™"' ; length of thorax, 

 2.5""" ; breadth of same, 2°"" ; length of abdomen, S.S""' ; breadth of same, 

 2 2"""; length of wing, 6.4"""; breadth of same, 1.8°""; length of hind 

 femora, 1.25"'™; of hind tibiae, 1.25"'"' ; of hind tarsi, 1.25""". 



Green River, Wyoming. TIn-ee specimens, Nos. 4112, 4135 and 4141 

 (F. C. Bowditch and S. H. Scudder), 40 (F. C. A. Richardson). 



