232 THE CANADIAN ENTOMOLOGIST 



De Selys' description (Bull. Acad. Belg. (2) XXI, p. 301) 

 agrees with the M. C. Z. types of hndsonica. Martin's figure 28 

 (Cordulines, Coll. Selys page, 27) is not the true hudso?iica but this 

 species walkeri, which is probably figured from a specimen in the 

 Selys' collection mislabeled hndsonica. Walkeri differs from 

 hudsonica in the superior appendages being closer together; in 

 lateral view, in that the tip is directed ventrad, while in htidsonica 

 it is directed caudad. - In walkeri the two basal teeth almost over- 

 lap in lateral view. In hndsonica, they are apart the width of either 

 tooth. 



In coloration walkeri is very dark, but in a large series of 

 semicircnlaris (Kennedy, Proc. U. S. N. M., 46, p. Ill,) and in a 

 large series of alhicincta in the Carnegie Museum there is much 

 variation in colour. 



This species has hndsonica as its nearest relative. For this 

 reason I have associated with this male the female found in the 

 M. C. Z. collection which is most like the type female of hndsonica 

 but seems to be specifically distinct. The female differs from the 

 the hndsonica female in darker coloration (as does the male) and 

 in the shorter sternum of segment 9. The only other females 

 with which these might be confused are those of the forcipata 

 group, but in none of these does the vulvar lamina exceed segment 

 9 in length. 



I take pleasure in naming, tliis species for Dr. E. M. Walker, 

 who has done so much work on our northern Odonate fauna. 



Somatochlora hudsonica (Hagen). 



This species resembles alhicincta, but is readily distinguished 

 by the greater width between the bases of the superior appendages 

 of the male. Until Mr. Whitehouse took this species at Red Deer, 

 Alberta, last summer, the only specimens in this country were the 

 types in the Museum of Comparative Zoology. The types are 

 2 cf's and 9, from Ft. Resolution, Hudson Bay Ter., Kennicott, 

 1861. See figs. 5-8. 



Somatochlora alhicincta (Burmeister) 

 Excepting possibly semicircnlaris this is the most common 

 species in collections. The finest series is that in the Carnegie 

 Museum from Mt. Ranier, Washington, collected by Jennings. 



