128 



Smith and Pritchard: Odonata 



Fig. 4:37. Wings of Somafoch/ora renebrosa 

 (Needham and Westfall, 1955). 



Genus Cordulia Leach, 1815 



This genus contains one species in North America, 

 C. shurtleffi Scudder 1866 (fig. 4:38). It is a bog- 

 loving species with a northern distribution. It occurs 

 in Canada and northern United States, but ranges as 

 far south as Utah and California in the West. The 

 naiads are thick set and hairy and occur in shaded 

 trashy areas at margins of ponds or bogs. 



Genus Somatochlora Selys, 1871 



Somatochlora is a large circumpolar genus inhabitating 

 the northern parts of the Palaearctic and Nearctic 

 regions (fig. 4:37). One species, S. semicircularis 

 (Selys) 1871, ranges from western Alaska south to 

 the high mountains of California, Utah, and Colorado. 

 The adults fly in sunny openings in wooded mountain 

 slopes or river valleys. The immature stages occur in 

 swamps or spring bogs. While feeding they fly at 

 heights of thirty to fifty feet or more. In the breeding 

 areas they fly back and forth low over the bog. Eggs 

 are laid in masses on the surface of the water in the 

 more open pools. These masses disintegrate and fall 

 to the bottom. For more details on the habits of this 



Fig. 4:38. Wings of Cordulia shurfleffi 

 (Needham and Westfall, 1955). 



Fig. 4:39. Wings of Tetragoneuria sepia 

 (Needham and Westfall, 1955). 



and other Somatochlora see Walker (1925) and Kennedy 

 (1913). 



Genus Tetragoneuria Hagen, 1861 



The genus Tetragoneuria contains brownish, non- 

 metallic dragonflies with the thorax heavily clothed 

 with hairs (fig. 4:39). The adults are of a roving 

 habit and most of the species are widely distributed. 

 They are sometimes very abundant at long distances 

 from water where in a clearing or along a road they 

 may be seen patrolling a few feet above the ground. 

 Two wide ranging species occur on the Pacific Coast. 

 The naiads are smooth, hairless, and with a depressed 

 abdomen. They are frequently very abundant along 

 the edges of ponds and streams where they crawl over 

 the bottom and loose trash. 



Key to California Species 



Males 



1. Dorsal appendages each with a strong dorsal tooth, the 

 medioventral tooth on inside short and blunt (Canada, 



northern U.S., Washington to California) 



canis MacLachlan 1886 



— Dorsal appendages each without a dorsal tooth, and the 

 medioventral tooth on inside long and slender (Canada, 

 northern U.S., Washington to California). 



spinigera Selys 1871 



Females 



1. Frons (as seen from above) with anterior margin pale, 

 abdominal appendages 2.3-2.7 mm. in length cants 



— Frons (as seen from above) with anterior margin black, 

 abdominal appendages 3.5 mm. in length spinigera 



Naiads 



1. Lateral spines of the ninth abdominal segment very 

 slightly or not at all divergent, six-tenths middorsal 

 length of segment canis 



— Lateral spines of the ninth abdominal segment strongly 

 divergent longer than middorsal length of segment 



spinigera 



