78 THE CANADIAN ENTOMOLOGIST. 



Cordiclia semiaquea, Burm. In Cornell Univ. collection labelled 

 " N. Y." ; it is probably from Ithaca; Mr. Pettit has taken it at Baldvvins- 

 ville, N. Y. 



Cordulia, sp. ? I have an abnormal female near C. cynosura, but the 

 hypertriagonal space of forewings crossed, the sectors barely united at 

 apex ; all the triangles crossed, no internal triangle to hind wings, three 

 or four veinlets under the pterostigma, black spots at base of the wings, 

 abdomen shorter than hind wings, sides of thorax without any stripe. 

 This and Naimodiplax vacua may serve to illustrate how fickle are the 

 venational characters in this family ; it would be better, I think, to draw 

 generic characters from the head and thorax. 



LlBELLULID^. 



Tramea lacerata, Hagen. I saw two specimens of this species at 

 Freeviile (a town ten miles from Ithaca), May 31, 1889; after much 

 trouble I captured one of them. 



Celthemis elisa, Hagen. One specimen collected by Prof Morgan. 



Libellula quadrimaculata, Linn. A few specimens in the Cornell 

 Univ. collection. 



Libellula pulchella^ Drury. Common during spring and summer. 



Libellula basalis, Say. Uncommon, August. 



Libellula irijiiaculata, De Geer. Common during spring and sum- 

 mer. This is usually placed in the genus Plathemis, which differs from 

 Libellula only in the male genital organs, which, I think, are hardly 

 worthy of generic rank. 



Mesothemis longipennis, Burm. Common during spring and summer. 

 I have a specimen with the triangles four-sided, 



Mesothemis simpHcicollis, Say. I have seen a specimen collected by 

 Mr. O. Takahashi. 



Diplax vicina, Hagen. Not uncommon, July, August. 



Diplax rubicundula, Say. Common during spring and summer, 



Diplax semicinta, Say. Uncommon, August. 



Diplax intacta, Hagen. This is placed in the genus Leucorhinia, 

 Britt., separated from Diplax only by structure of the vertex of head; the 

 venational characters vary to the usual form of Diplax. Not uncommon 

 in the spring. 



