MAY PLIES AND MIDGES OF NEW YORK 109 



joint large, but not long; the eight following joints suboval; the 

 five terminal joints long, not dilated, cylindric, each being twice 

 the length of the preceding ones; eves reniforni, large, wider be- 

 nealh. and approaching above; steinniata none; palpi arcuated, 

 four-jointed, fust joint shortest, last joint longest; proboscis 

 shorter than the head; thorax subglobular, convex above and pro- 

 jecting a little forward acutely before; beneath convex; scutel 

 transverse; wings moderate, somewhat lanceolate; poisers naked; 

 feet unequal; anterior pair with the coxae somewhat elongated; 

 thighs dilated, and with a series of spines on the lower side; 

 tibiae arcuated, accurately closing on the inferior, surface of the 

 thigh; tarsi moderate; intermediate pair slender, longer than the 

 auteriors; third pair longest, slender, the tarsi elongated, termi- 

 nated by a single long and slender nail. 



In specimens of Heteroniyia fasciata Say, I find the 

 wing has the crossvein-like R 2 though very delicate and indistinct. 



Walker's description of Pachyleptus agrees exactly with 

 that of Say. Arribalzaga (1893) redescribes the genus at length 

 for a specimen in his possession. Heteroniyia fasciata 

 Say, differs from Arribalzaga's description of Pachyleptus 

 in the following particulars: Face convex and not keeled; the 

 apical joint of the palpus is longer than the second and third, 

 which are subequal ; and the hind tarsi which are much elongated 

 have only the first and second joints subequal, the others being 

 shorter. As these differentiating characters are of specific rather 

 than generic importance, I think Pachyleptus should be 

 considered a synonym of H e t e r o m y i a . 



In one particular only may there be a chance that the two 

 genera are distinct. In Walker's description nothing is said of 

 the wing venation excepting the statement that the veins are like 

 those of Ceratopogon in structure ; but Arribalzaga states 

 that Ro is wanting. This condition agrees with the figure given 

 by Say I |d..'!T. lig.Sj. In the type species, however (IT. fas- 

 ciata ), this vein is present, at least in all the specimens that 

 I have seen, although it is quite delicate and indistinct. Should 

 it be found that certain species do have this vein and others do 

 not, the former may be called Heteroniyia and the latter 

 Pachyleptus Arribalzaga i -Pachyleplus Walker?) 



There are several North American species. 



