506 NEW YORK STATE MUSEUM 



Dorocordulia lepida Selys 



1871 C o r (1 u 1 i a lepida Selys, Acad. Belg. (2) Bui. 31 : 264 



1872-75 Cordulia lepida Hagen, Bost. soc. nat. hist. Proc. 15 : 270 and 



18:60 

 1895 Somatochlora lepida Calvert, N. Y. ent. soc. Jour. 3 : 46 (listed 

 from Albany) 

 This species was originally described from specimens sent from 

 Albany; it seems not to have been taken in the state since that time. 

 Its nymph is unknown. 



Dorocordulia lintneri Hagen 



1854 Emmons, Agric. N. Y. v. 5, pi. 15, fig. 1 (colored fig. : no 



name or description) 

 1878 Cordulia lintneri Hagen, Acad. Belg. (2) Bui . 45 : 187 

 1890 Cordulia lintneri Hagen, Psyche, 5:272, pi. 1, fig. 10-17 (a full 



account) 

 1895 Somatochlora lintneri, Calvert, N. Y. ent. soc. Jour. 3 : 46 (listed 



from Center, Albany co.) 



Bat few specimens are known of this very interesting species, which 

 has a distribution from New York to Saskatchewan. Its nymph is 

 unknown. 



Subfamily libe^llulinae 



This extensive group includes the commonest and best known of all 

 our Odonata. The imagos are familiar figures above every pond and 

 ditch, and by every roadside. The nymphs are less well known, not- 

 withstanding their relative abundance, than in some of the smaller groups. 

 Our tables which follow are the first to be given for American forms, 

 and the descriptions also are entirely new, with the exception of the 

 nymphs of P a n t a 1 a and T r a m e a, which alone have been described 

 by Cabot. The following keys will serve for the separation of both 

 nymphs and imagos. 



KEY TO GENERA 



Imagos 



a Triangle of the fore wings four-sided; anal loop poorly developed, not foot- 

 shaped Nannothemis p. 509 



aa Triangle of the fore wing fully differentiated, three-sided; anal loop well 



developed and foot-shaped 



h Triangle of the fore wing with its front and inner sides meeting by an angle 



of about 100^ ; the subtriangle without cross veins; the vein which 



bisects the anal loop straight Perithemis p. 511 



