504 NEW YORK STATE MUSEUM 



DOROCORDULIA geil. HOV. 



Cordiilia libera Selys, type 



The three species here separated from Somatochlora and placed 

 in this new genus differ from Somatochlora by a number of 

 important venational and other characters, among which are the following : 



1 The triangle of the fore wing is open : it is traversed by a cross vein in 



Somatochlora. 



2 There are never more than two complete rows of cells beyond the triangle in 



the fore wings : there are more than two in Somatochlora. 



3 The second cubito-anal cross vein (and, therefore, an interual triangle or sub- 



triangle) is wanting in the hind wing ; it is present in Somatochlora. 



4 There is a long space beyond the single cross vein under the stigma: in 



Somatochlora the spaces are more nearly equal, and there are often 

 two cross veins under the stigma. 



The Cordulia lintneriof Hagen may not belong here : in 

 fact it may belong in the subfamily Libellulinae. I leave it here beside 

 the species with which it has been associated pending farther study, and 

 awaiting the discovery of its nymph. It will be found not to agree with 

 characters 2 and 4 of the above statement. 



This genus is more closely aUied to Cordulia than to Somat- 

 ochlora, but it differs from Cordulia by characters i and 2 as 

 stated above, as well as by the lack of the deep bifurcation of the inferior 

 appendage of the male which is characteristic of Cordulia. The 

 nymph also, I found much more easy to distinguish from that of 

 Somatochlora elongata than from that of Cordulia shurt- 

 1 e f f i. The nymph is known for the single species D. libera. 



Our imagos are readily separable into species by the following key : 



a Abdomen with segments 7 to 10 spatulately dilated libera 



aa Abdomen gradually and very moderately widened at apex 



& The articulations of the abdominal segments yellow le pida 



hh The articulations of the abdominal segments not yellow lintneri 



Dorocordulia libera Selys 



1871 Cordulia libera Selys, Acad. Belg. (2) Bui. 21:262 

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

 from the Catskill mountains) 



This dainty and beautiful corduline species was not uncommon at 

 Saranac Inn. But few specimens were taken, because no special effort 

 was made to get them. The imagos obtained were taken when flying 

 with Cordulia shurtleffi about the borders of the bog ponds 

 mentioned under the account of that species. They are less swift of 



