48 PAPERS ON ZOOLOGY OF MICHIGAN. 



AA. Face transversely banded with black. 



D. Yellow ot the thoracic dorsum reduced to two narrow, oblique, isolated, 

 yellow stripes. 



G. scudderi 



DD. Yellow stripes cf the thoracic dorsum broader; anterior face of the 

 hind femora yellow. 



G. vastus 



Xymphs. 



In the following key Gomphus rentricosus is iiot included since the nymph of that species is 

 unknown. 

 A. Four pairs of lateral spines. 



B . Dorsal hooks more or less apparent on segments two or three to nine. 



G. descriptus 



BB. Dorsal hooks represented only by teeth on the posterior margins of eight and 

 nine. 



CC . Lateral spines on nine about as long as the tenth segment. 



G. vastus 



CC . Lateral spines on the ninth segment about half as long as segment ten. 



G. scudderi 



AA. Three pairs of lateral spines, the first pair very small. 



G. spicatus 



Gomphus spicatus Hagen. — Nymphs of this species were taken in 

 Maple River near its source. Their habitat is probably the stream 

 vegetation. No adults were taken. 



Gomphus ventricosus Walsh. — This species was reported from the 

 region in 1910 but did not occur in any of the 1914 collections. 



Gomphus descriptus Banks. — Only the nymphs of this species were 

 taken at one station on Maple River, 



Gomphus scudderi Selys. — This species was not taken in 1914 al- 

 though adults were reported from the region in 1910. 



Gomphus vastus Walsh. — Nymphs of this species were taken in 

 Bessey Creek where they seemed to prefer the bottom of the stream 

 and the lower pa^rts of the vegetation. 



SUBFAMILY AESHNINAE. 



Large numbers of nymphs representing six of the eight species of this 

 subfamily found in the Douglas Lake region were collected, but the 

 adults of only four species were taken. These species Epiaeschna 

 heros (Fabricius), Basiaeschna janata (Say), Aeshna constricta Say and 

 Anax Junius Drury were very common. 



Imagos. 



A. Upper part of the arculus equal to or longer than the lower part; anal loop five to seven: 

 sided. 



B . Radial sector forked. 



C . Radial sector forked near the middle. 



Epiaeschna 



CC. Radial sector forked beyond, i. e. apicad to the middle. 



Aeshna 



