164 THE CANADIAN ENTOMOLOGIST 



naga River, collected by Mr. Paul Hahn, which differ very slightly 

 from those of B. grafiana. The latter were also found on the same 

 river. As vinosa and grafiana are the only North American species 

 of Boyeria, and are both common in this region, there can be no 

 doubt that the species not yet reared is B. vinosa. 



The nymphs of these two forms may be separated as follows: 



Mentum of labium, 5.5 mm. long, its middle breadth scarcely less 



than half its length; fourth abdominal segment without lateral 



spines; lateral abdominal appendages of female one-fourth to 



one-third as long as the inferior appendages, and usually about 



as long as the dorsum of segment 10 B. vinosa. 



Mentum of labium 6.5-7 mm. long, its middle breadth distinctly 

 less than half its length; fourth abdominal segment generally 

 with distinct though very small lateral spines ;lateral abdominal ap- 

 pendages of female, one-fifth to one-fourth as long as the inferior 

 appendages, and one-half to three-fifths as long as the dorsum 



of segment 10 B. grafiana. 



B. grafiana also differs from B. vinosa in the slightly stouter 

 inferior abdominal appendages, which are less incurved at the tips, 

 and in the slightly larger size as shown by the following measure- 

 ments: 



B. vinosa. — Length of body 34-36.5; hind wing 6-7.5; hind 

 femur 5-6; width of head 7.5-8. 



B. grafiana. — Length of body 37-39; hind wing 7.5-8; hind 

 femur 6-6.5; width of head 8-8.5. 



In coloration the nymphs of these two species are quite simi- 

 lar, except that the pale, wavy, dorso-lateral streak on each side 

 of the abdomen is usually quite distinct, in grafiana, but more or 

 less obscure in vinosa. In both species the depth of coloration 

 varies considerably, usually being a rather dark brown. All the 

 nymphs from the Go Home Bay district are very dark in colour, 

 but the pale bands of the abdomen and legs are quite sharply de- 

 fined. The most characteristic mark of Boyeria nymphs is a pale 

 oval or diamond-shaped median blotch in the dorsum of segment 8. 



Neiirocordulia yamaskanensis (Prov.) Selys. 

 The nymphs of this interesting species are common at Go 

 Home Bay and in the Muskoka Lakes district. They cling to the 

 under sides of boulders, along the more exposed rocky shores or 



