Vol. xxiv] ENTOMOLOGICAL NEWS 315 



above synopsis. The appendages may be quite similar to 

 those of selysii. The known habitats of the two forms are 

 far apart. 



It will be noticed that, in spite of its geographical distribu- 

 tion, integricollis is nearer structurally to the European and 

 Brazilian species than to the two already known from the 

 United States. 



Dr. F. Ris, within recent years, has described* color vari- 

 eties in Swiss specimens of N. speciosa which may possibly 

 indicate a color dimorphism or polymorphism among the fe- 

 males analogous to that known in Ischnura. In this connection 

 it is of interest to note that I found a single female of A r . Irene 

 from Manchester, Maine, June 12, 1899, by Miss Mattie 

 Wadsworth (now in the collection of Mr. E. B. Williamson!), 

 which has abdominal segments 8 and 9 colored as in the male 

 of Irene and unlike the majority of females as stated above. 

 The alternative coloring of segment 8 in the female of gracilis 

 mentioned above is seen in one specimen from lona, New 

 Jersey, July 13, 1902 (Daecke). 



The transference of species from Nehalennia to Ischnura, 

 mentioned in the first paragraph of this paper, indicates the 

 difficulty of sharply distinguishing these two groups. Even 

 now it does not appear to be possible to give any one char- 

 acter which will invariably separate them. The following 

 statement may be of assistance : 



Nehalennia. Prevailing color of dorsum metallic green. 

 Second joint of antenna black, its middle third pale. Pale 

 color on postero-superior part of head forming a transverse 

 line whose extremities are not enlarged (except in ? inte- 

 gricollis male). M2 on the hind wings separating from Mi 

 more often nearest the fourth postnodal. Males without an 

 elevated, bifid, dorsal process on abdominal segment 10 (ap- 



* Farbenvarietaten der Agrionide Nehalennia speciosa Charp. Mitt, 

 schweiz. entom. Gesell. XI, pp. 159-165, 1906. Very recently this species 

 has also been discovered in Asia by Bartenef, Zool. Anz. xxxv, p. 278, 

 1910; Ann. Mus. Zool. Acad. Imp. Sci. St. Petersb. xvi, p. 447, 1912. 



t Mr. Williamson kindly placed his collection of Nehalennia at my 

 disposal for study. 



