140 DIPTERA OP NORTH AMERICA. [PART III. 



dinal vein. The posterior crossvein is covered by a brownish- 

 black spot, which is especially expanded near the posterior margin 

 and the anterior end of which is connected by an ochre-yellowish 

 or somewhat brownish-yellow coloring with the third spot of the 

 anterior margin, thus forming a complete crossband, somewhat 

 expanded posteriorly and tinged with yellowish in the middle. 

 Sometimes, however, the brown spot upon the posterior crossvein 

 is somewhat more isolated from the yellowish coloring and extends 

 in the direction of the half-crossband, formed by the fourth spot 

 on the anterior margin. This less common variety is the one 

 described by Say, 1. c. ; the ordinary picture is represented on 

 Tab. VIII, f. 29, of the present volume. On the anterior side 

 of the sixth longitudinal vein there are two black spots of only 

 moderate size and rounded shape. Of them, the second only 

 crosses that vein, gradually to fade away. Between the second 

 costal spot and the second of the two spots of the sixth vein, 

 there is a very large oval ochre-yellowish or more brownish- 

 ochreous spot; it reaches on one side as far as the posterior basal 

 cell, and assumes within the marginal cell a rather dark-brown 

 coloring. The veins of the wing are black or brownish-black 

 inside of the picture, clay-yellow elsewhere. The third and 

 fourth longitudinal veins converge towards their end a little more 

 than in the preceding species. 



Eab. United States. 



Observation.— I possess six female specimens and no male, but 

 have seen the latter in other collections. It does not show any 

 perceptible difference from the female, except in the sexual marks. 



Gen. III. CAIXOPISTRIA nov. gen. 



Charact. — General appearance almost Trypeta-like. 



Front exceedingly broad, with impressed punctures; cheeks com- 

 paratively broad ; clypeus somewhat projecting over the edge of the 

 month, sometimes withdrawn inside of the oral opening. 

 Wings with an unusually convex posterior margin ; posterior cross- 

 vein very oblique, its anterior end much more approximated to the 

 apex of the wing, than the posterior end ; the posterior angle of the 

 anal cell is drawn out in a very long, acute lobe. 



The species upon which this genus is based, cannot well be 

 placed in the genus Stictocephala on account of the remarkable 

 difference in the outline of the wings as well as in the venation. 



