1908] The Dragonflies of the Ottawa District. 53 



thorax yellowish green v/ith a narrow brown streak on each 

 side of the middle line ; superior appendages of the male bifurcat- 

 ed, the inferior appendage prolonged into a pair of widelv 

 divergent cur\"ed processes. 



This is the first notice of this remarkable Gomphus from 

 Canada. It has also been taken in Illinois and Iowa. 



Sub-family CORDULEGASTERIXAE. 



Genus Cordulegaster Leach. 



We have several species of this genus, inhabitants of small 

 creeks and runways from springs. Owing to the nature of their 

 habitat they are local in distribution though C. maculatus is 

 sometimes abundant where it occurs. 



24. Cordulegaster diastatops Selys. 



One male, segs. 6-10 wanting (Maclaughlin). 



This species may be known from others of the genus by 

 the eyes not being contiguous above and the abdomen being 

 marked with yellow lateral somewhat triangular spots, their 

 apices directed backwards. 



It has also been taken at Port Sidne}', Muskoka, with C. 

 maculatus. According to Needham the nymph inhabits upland 

 spring bogs. 



Sub-family .^SHNIN.^v. 



Genus Anax, Leach. 



23. AxAx juxius (Drury), Selys. 



Ottawa, May 6th, 1899, 1 male in cop.: June 24th, 1899. 

 1 male (Fletcher). 



This is one of our largest and swiftest dragonflies, and its 

 great size, bright green thorax and blue abdomen render it quite 

 unmistakable for any other species. > The blue color, how-ever, 

 is seldom seen in dried specimens and even in life does not de- 

 velop for some time after the green color of the thorax has been 

 assumed. 



It is the first dragonfly to appear in the spring, being on the 

 wing in the vicinity of Toronto as early as the second week in 

 April. It flies throughout May and June, but is seldom seen 

 in July and August, appearing again however in September. 



Genus Aeshna, Fabricius. 



The members of this genus are the large blue- or green- 

 spotted forms which are often so numerous in late summer and 

 early autumn. The genus is distinguished from the other 

 genera of Aeshninas mentioned here by the fact that the sub- 

 nodal sector is apically forked, the fork being unsvmmetrical. 



The North American species are now undergoing a revision 

 bv the writer and it has been found necessarv to alter the 



