122 DIPTERA OF NORTH AMERICA. [PART III. 



Upon the pleurae the pollen is perceptibly less dense than upon 

 the thoracic dorsum, so that they appear shining. Upon the 

 sides of the scutellum the pollen is thick and not interrupted, 

 while that upon its disk somewhat resembles the pollen on the 

 surface of the thoracic dorsum, only it is a little thinner and 

 has no distinct pollenless dots. The abdomen is shining black, 

 covered, towards the basis, with a gradually increasing, uninter- 

 rupted, but not very thick ash-gray pollen. The first joint of the 

 flattened ovipositor is shining black, very broad, but little 

 narrowed towards its end, with somewhat convex sides and com- 

 paratively shorter than that of T. luridipennis. Feet black or 

 brownish-black; the extreme tip of the femora, the basis and 

 extreme tip of the tibiae, as well as the tarsi, yellowish-red ; 

 however, the last three or four joints of the fore tarsi and the 

 last two joints of the hind tarsi, brownish-black. Wings rather 

 hyaline, gray, with a delicate tinge of brownish-clay-yellow, 

 without any picture. 



Hab. Illinois (Osten-Sacken). 



Gen. III. TEPHROIVOTA Loew. 



Charact. — Head high and short. Front of a moderate and equal breadth, 

 comparatively long. Face rather sharply carinate, only little pro- 

 truding in front of the eyes in profile ; almost vertical. The 

 vertical diameter of the eyes almost double the size of the hori- 

 zontal one. Anterior edge of the mouth not drawn upwards. 

 Cheeks very narrow. 



Antennae of a medium length; the first two joints short; the third 

 ending at a sharp angle, although not excised above. 



Thorax upon its middle with bristles on the hind part only ; covered 

 with a gray dust. 



The first longitudinal vein with bristles upon its end only; the end of 

 the fourth longitudinal vein not curved forward; the posterior 

 angle of the anal cell, although sharp, is not extended in the shape 

 of a lobe. 



This genus contains only small-sized species, which, in their 

 whole organization, approach the species of Pteropaectria ; this 

 is still more the case with the European species, than with the 

 only American one which I know. The latter, however, agrees 

 in so many characters with the European Tephromotae, that it 

 can be placed, without any hesitation, in that genus. Its antennae 

 are a little shorter and their third joint somewhat broader ; the 



