MAY FLIES AND MIDGES OP NEW YORK '51 



Legs rather short, nearly bare; femora scarcely flattened, but 

 somewhat concave on the side applied to the body; pale brownish, 

 paler at the sutures. Wing cases reaching posteriorly as far as 

 the apex of the 3d abdominal segment. 



Abdomen very slightly depressed, regularly tapering posteriorly, 

 its segments very slightly increasing in length to the 9th, the 10th 

 a little shorter on the dorsum, where produced (backward in a 

 rounded lobe, one half shorter at the sides; short lateral spines 

 on segments 8 and 9, larger on 9, the lateral angles of the pre- 

 ceding segments obtuse. 4 



Gills present on segments 1-7, double, similar, or slightly 

 longer on the middle segments, divided in nine tenths of their 

 length into two long, slender, simple tapering filaments, pig- 

 mented with purplish along the tracheae. tSetae 3, equal, nearly 

 bare at base and sparingly whorled with spinules beyond, grad- 

 ually tapering to long slender tips. 



General color olivaceous, paler below, with a very narrow 

 median pale line on head and prothorax, a median row of pale spots 

 on the abdomen of the female becoming larger posteriorly, and a 

 pair of spots either side on segments 3-9, becoming confluent with 

 the median one on 9 ; male darker and more uniformly brown. 



May 8, 27, 30, 31 ; June 13, 14, 18. 



Heptageninae 



I deem it necessary to state that I have scarcely entered into 

 the study of this interesting and difficult complex of interrelated 

 forms, having dealt at first hand only 

 with those species" in whose life his 

 tories I have become interested. The 

 foregoing keys for this group of genera 

 are based largely on characters culled 

 from Eaton's Monograph, and these are 

 but a few of the many characters 

 therein given, and the value of these 

 few as absolute distinctions of closely 

 allied genera I have not personally 

 tested. This group should furnish a 



. . ner appendages 



most inviting field for some special 



student, especially here in North America, where it is so abund 



antly represented. 



In this group the independent specialization of the nymphs is 

 extreme. Their life is 1 relatively long, and the conditions under 



