AQUATIC INSECTS IN NEW YORK STATE 



245 



Argia translata Ha gen 



1SG5 Argia translate Hagen, Acad. Belg. Bui. (2) 20:410 

 1901 Argia translata Calvert, Eut. News. 12:326 (recorded from 

 New York State) 



This species, discovered in our State by Dr Calvert at White 

 Lake, Sullivan co., Aug. 2, 1898, was previously recorded only 

 from Venezuela. Its nymph is unknown. 



CHROMAGRION gen UOV. 



Since the repartition of the old genus Agrion in 1876, the 

 North American Agrion conditum of Hagen has gener- 

 ally been written ?Erythromma conditum, its affinity 

 with Erythromma being doubtful on account of notable differ- 

 ences in venation, in form of abdominal appendages and in type 

 €f coloration between this species and the typical species of the 

 genus. The discovery of the nymph now gives opportunity for 

 comparison of nymphal characters; the differences here are 

 equally noteworthy. A tabular comparison of the principal 

 characters of the nymph of our species with the nymphs of 

 typical species of Erythromma and Pyrrhosoma (the only genera 

 with affinities close enough to make such comparison necessary) 

 will make clear the reasons (added to the well known differences 

 of images) for proposing the establishment of a new genus. 



CHARACTER OF 

 NYMPH 



Hind angles of 

 head 



Oills 



Mental setae of 

 labium 



Lateral setae 



CHROMAGRIOX 



(A. conditum type) 



strongly angulate 



long and narrow, 

 widening al- 

 most to the tip. 

 then suddenly 

 contracted, then 

 pointed 



3 and a rudimen- 

 tary 4th 



End of lateral squarely truncate, 

 lobe of labium,! angled supe- 

 above end hooli riorly scarcely 

 denticulate 



ERYTHROMMA 



strongly angulate 



broad, oblong 



with parallel 

 sides, obtusely 

 rounded on tip 



3-4, usually 4 



&-7 



less square, with 

 3 strong teeth 



PYRRHOSOMA 



rounded 



oblanceolate, con- 

 tracted near tip 

 and then point- 

 ed 



1, and a rudimen- 

 tai-y 2d 



7-8 



obliquely trun- 

 cate, rounded 

 superiorly and 

 not denticulate 



