1908] The Dragonflies ^f the Ottawa District. 59 



40. DoROCORDULiA LIBERA (Selvs) , Needham. Fig. 17. 

 Ottawa, July 7th, 1907, 1 male (Young). 



This is the daintiest and most beautiful of our Cordulinae. 

 It is about 40 mm. long, bronze-green with bright green eyes. 

 Segments 3 to 5 are very slender, especially in the male, while 

 6 to 9 are considerably dilated. The undivided triangle of the 

 fore wings and the form of the male appendages will serve to 

 distinguish it from certain species of an allied genus, Soniatochlora, 

 representatives of which are sure to be found about Ottawa. 



D. libera is found about the marshy borders of lakes in early 

 summer. 



Sub-family LIBELLULIN.^. 



Hind margin of eyes without a tubercle, males without 

 auricles on segment 2, anal margin of hind wings not excavated. 



Most of our familiar dragonflies belong here and are to 

 be found flitting about every pond and marsh. 



Among the species not recorded below which may be looked 

 for in the vicinity of Ottawa are Xamwthemis bella (Uhler) 

 Brauer, Leucorhinia proxinia Calvert, L. jrigida Hagen, L. glacialis 

 Hagen, Sympeinun scoticum (Donovan) Newman, and Celithemis 

 elisa (Hagen) Walsh. 



Genus Leucorhinia, Brittinger. 



The species of this northern genus resemble those of 

 Sympeirmn in form and size, but difi^er in certain structural 

 details and in coloration. The pterostigma is shorter than in 

 Sympetrum, being only about twdce as long as broad; the face 

 is pure white, and there is always a few black markings at the 

 base of the wings. 



The species appear in the spring or early summer and have 

 for the mo.st part disappeared by the time the Sympetra make 

 their appearance. 



41. Leucorhinia hudsonica (Selvs) Hagen. Figs. 18, 

 19. 



Hull, June 29th, 1886, 1 female (Fletcher): Eastman's 

 Springs, Ont., May 15th, 1903, 1 female (Fletcher). 



This small species is widely distributed in Canada in the 

 Boreal Zone. It is black with irregular yellov/ I'lotches on the 

 sides of the thorax and a row of dorsal abdominal spots on seg- 

 ments 2 to 7 or 8. There are two black dashes at the base of 

 the fore wings, another at the base of the hind wings, and be- 

 hind this is a larger triangular basal spot. The form of the 

 male appendages and vulvar lamina of the female is characteristic. 



42. Leucorhinia intacta (Hagen), Hagen. Figs. 20, 21. 

 Ottawa, May 24th, 1903, 1 male (Gibson): May 28th. 1Q04, 



