AQUATIC INSECTS IN NEW YORK STAT© 



245 



Argia translata Hagen 



1865 Argia translate Hagen, Acad. Belg. Bui. (2) 20:410 

 1901 Argia translata Calvert, Ent. 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. 



CHRosiAGRioN gen nov. 



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

 North American Agrion conditum of Hagen has gener- 

 ally been written ?E r y t h r o m m a conditum, its affinity 

 with Erythromma being doubtful on account of notable differ- 

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

 of coloration between this species and the typical species of the 

 ^enus. 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 

 NTMPH 



Hand angles of 

 head 



■Gills 



Mental setae of 

 labium 



Lateral setae 



End of lateral 

 lobe of labium, 

 above end hook 



CHROMAGRION 

 (A. conditum type) 



strongly angulate 



loOg and narrow, 

 widening al- 

 most to the tip, 

 then suddenly 

 contracted, then 

 pointed 



3 and a rudimen- 

 tary 4 th 



squarely truncate, 

 angled supe- 

 riorly scarcely 

 denticulate 



ERYTHROMMA 



strongly angulate 



broad, oblong 



with parallel 

 sides, obtusely 

 rounded on tip 



3^, usually 4 



6-7 



less square, with 

 3 strong teeth 



PYRRHOSOMA 



rounded 



oblanceolate, con- 

 tracted near tip 

 and then point- 

 ed 



1, and a rudimen- 

 tary 2d 



7-8 



obliquely trun- 

 cate, rounded 

 superiorly and 

 not denticulate 



