88 DIPTERA OF NORTH AMERICA. 



exteriorly, placed at the end of the second third of the discal cell ; 

 posterior transverse vein steep. 



Hah. Pennsylvania. (Osten-Sacken.) 



21. T.l>ella Loew. ^andj. (Tab. II, fig. 23.) — Flavo-cinerea, capite, 

 pedibus abdoniineque luteis, boc apicem versus nigricante, alis nigro- 

 reticulatis, in apice radiatis, guttis disci paucissimis, pone venulam 

 transversam nulla. 



Yellowish gray ; bead, legs, and abdomen yellow, the latter blackened 

 towards tbe end ; reticulation of the wings radiating at the apex, black, 

 with very few drops in the middle ; no drops at all beyond the small 

 transverse vein. Long. corp. % 0.12 — 0.13. £ 0.13 — 0.15. Long. al. 

 0.11—0.12. 



Head rather pale yellow, front and antenna? sometimes darker, 

 the former being of middle breadth, slightly narrowed anteriorly. 

 Face rather narrow, nearly perpendicular, slightly excavated, the 

 anterior border of the mouth again projecting a little. Antenna? 

 yellow, reaching to nearly the border of the mouth ; the third joint 

 somewhat broad, with the bristle having an extremely short, hardly 

 visible pubescence. Opening of the mouth very large, a little raised 

 anteriorly. Proboscis and palpi rather large. Cheeks descending 

 a little beneath the eyes. Thorax yellowish-gray. Scutellum of 

 the same color, pale yellow at the tip, to a larger or smaller 

 extent, with four bristles. Metanotum black, but dark gray from 

 its beiug dusted with paler. Abdomen dark yellow, black towards 

 the extremity ; well preserved specimens show distinctly that this 

 black color is produced by each of the last segments having two 

 large blackish spots, which leave an intermediate streak, and the 

 posterior border yellow; in most specimens these black spots are 

 not distinct, or only the hind borders of the last segments are 

 paler. Borer black, rather broad, narrower towards the end, flat, 

 little longer than the two last segments taken together. Legs 

 yellow. Hairs of the whole body and all bristles yellowish, only 

 the very short hairs of the borer being black. The reticulation of 

 the wings is blackish-brown, leaving only the innermost base of 

 the wing free, with the exception that it has some blackish spots. 

 In the middle of the wing there are so few clear drops, that the 

 black color is not only continuous, but also occupies most part of 

 the surface ; in the sub-marginal cell there is only one clear drop, 

 near the hind side of the second longitudinal vein and alittle beyond 

 the small transverse vein. Between the third and fourth lon^itu- 



