AQUATIC INSECTS IX NEW YORK STATE 315 



b Snprfispimcular setae of the first six abdomiual segments forming a 

 single continuous group of setae 

 c Sternal setae of the fifth abdominal segment divided longitudinally 

 by a mesal line into two groups; the posterior sternal setae of the 

 mesothomx undivided 

 d Sternal setae of the seventh abdominal segment distinctly di- 

 vided into two groups; the iufraspiracular setae of the seventh 

 abdominal segment not longer than broad. ..ciucticornis 

 dd Sternal setae of the seventh abdominal segment continuous; the 

 iufraspiracular setae of the seventh abdominal segment twice 



as long as broad p a 1 m a t a 



€C Sternal setae of the fifth abdominal segment not divided; the pos- 

 terior sternal setae of the mesothorax not divided longitudinally 

 into two groups 

 d Supra spiracular setae of the sixth and seventh abdominal seg- 

 ments coalesced with the outer ends of their posterior tergal 



setae subtilis 



dd Supraspiracular setae of the sixth and seventh abdominal seg- 

 ments not extending as far caudad as the posterior tergal setae 



p r o s i c 1 1 i s 

 hh Supraspiracular setae of the first six abdominal segments divided 



transversely into two well marlied groups aequalis 



aa Supraspiracular setae of the first five abdominal segments extending 

 caudad as far as the caudal margin of the posterior tergal setae 



emarginata 

 Pupa 



a Antennae with the third segment distinctly longer than the second 



p a 1 m a t a 

 ca Antennae with the second and third segments subequal 



I) Prothorax distinctly tuberculate on the side; the pronotum with an 



impressed line at middle aequalis 



hh Prothorax not tuberculate on the side; the pronotum not with an 

 impressed line at middle 

 c First abdominal segment as long as, or longer than, the next four 

 segments 

 d Mesosteruum between the coxae nearly as broad as the coxae 



cincticornis 

 dd Mesosteruum between the coxae about one half the width of the 



coxae or less subtilis 



cc First abdomiual segment as long as the next three segments 



emarginata 

 Imago^ 



<z Head and thorax evidently pubescent above 

 h Elytra without pubescence 



c Posterior femora with a small tooth h i r t i c o 1 11 s 



CO Posterior femora simple pubicollis 



hb Elytra evidently pubescent; posterior femora toothed, .pubescens 



iThls table was compiled from a table by Charles W. Leng. Revision 

 of the Donaciae of Boreal America. Am. Ent. Soc. Trans. 1S91. 17:159-76. 



