180 THE CANADIAN ENTOMOLOGIST 



name. Resohitum is abundantly distinct from interrogatiim, but 

 is more closely related to it than is C. angulatiim, the only other 

 North American species of Ccenagrion. 



These three species of Ccenagrion may be separated as follows : 



A. Venter of thorax wholly pale; abd. segs. without lateral black 

 streaks close to the tergal margins; seg. 1 without lateral 

 black markings (except a fine transverse line near apical 

 margin). 



a. Underside of head black, with a broad yellowish 

 ocular margin; without a pale occipital marginal 

 line; seg. 2 in the male with a transverse black 

 spot, not connected with the apical black ring; 

 seg. 8 of female with a pale basal 

 ring angidatum Walk. 



aa. Underside of head yellowish; a pale marginal occi- 

 pital line; seg. 2 of male with a black dorsal spot 

 connected by a stalk with the apical black ring; 

 seg. 8 of female without a pale basal 

 ring resoluium (Selysj 



AA. Venter of thorax with a transverse black band behind the 

 posterior legs, connected with a Y-shaped spot; some of the 

 abd. segs. with black lateral streaks close to the tergal 

 margins; seg. 1 with an oblique or angular black lateral 

 spot inter rogatu m (Selys) 



The three specimens of C. interrogatnm from Nipigon, Ont., 

 were taken on June 19, 1913, from a marshy clearing on the shore 

 of the Nipigon River. Three of the Newfoundland specimens 

 were captured on July 27, 1914, in an open marsh at the mouth 

 of a small trout stream emptying into a small lake. The other 

 was taken on July 29 in a small reedy marsh, bordering a small 

 lake, surrounded by dense woods. Both of these lakes are mere 

 expansions of small streams, abounding with brook trout. Dragon- 

 flies were exceedingly scarce here, in spite of apparently favorable 

 conditions. This was perhaps due to the great numbers of trout 

 present. 



