DRAGONFLIES OF DOUGLAS LAKE REGION. 45 



SUBFAMILY COENAGRIONINAE 

 KEY TO rilE GENERA OF CEONAGRIOXI XAE. 



Imagos. 



A. No postocular spots; dorsum bronzy green. 



Nehalennia 

 AA. Light, round or ovoid, postocular spots. 



B . Sexes unlike in color, female with the orange oi the abdomen covering less than 

 the three basai segments of the abdomen; males chiefly black or green with a 

 bifid process on the apical margin of the 10th abdominal segment; pterostigma 

 rhomboidal. 



Ischnura 

 BB. Color of the males and females similar, females somewhat lighter; no upturned 

 bifid process on the apical margin of the 10th abdominal segment. 



Enallagma 



Nymphs. 



A. Labium with one mental setae and a rudimentary second one; antennae six jointed. 



Nehalennia 



AA. Labium with three to five mental setae; antennae seven jointed. 



B . Labium with four to six lateral setae; usually three mental setae on each side. 



Enallagma 



BB . Labium with five or six lateral setae; four mental setae. 



Ischnura 



GENUS NEHALENNIA SELYS. 



Nehalennia irene Hagen. — This species was not taken in any of the 

 collections at Douglas Lake during the summer of 1914 but was re- 

 ported as common during July and August, 1910. 



GENUS ENALLAGMA CHARPENTIER. 



Two Species of this genus, the males of which may be tlistinguished 

 by the following key, are known from the Douglas Lake region. 



Imaoos. 



A. Dorsum of segment two blue with an apical black spot. 



E. carunculatum 

 AA. Dorsum of segment two black. 



E. exulaiis 



Enallagma carunculatum Morse. — This species was reportetl to be 

 common in the region throughout the summer of 1910. No habitat 

 data were given. 



Enallagma exulans Hagen. — Specimens of these nymphs were taken 

 on Maple River. They were found clinging to the vegetation near 

 shore in very little water. The species has also been found in the water 

 of North Fishtail Bay. 



