AQUATIC INSBOTS IN NEW YORK STATE 



259' 



ISCHNURA 



This cosmopolitan genus contains a few very common and 

 widely distributed and well known species. I include three in 

 this paper, one of which I. p o s i t a , has been referred hitherto- 



Fig-. 12 Labia of Enallagma and Ischnu'ra ; a and 6, labium ofB. signatum; 

 candd,of I. verticalis 



to Nehallennia. The one reason for referring it to Nehallen- 

 nia, the absence of a spine on the apex of the sternum of the- 

 eighth abdominal segment in the female, appears not to be a 



Fig. 13 Eggs oflschnura verticalis 



good one, since a number of species are now referred to Ischnura 

 lacking that spine. Ischnura and Enallagma are not very 

 sharply defined from each other, and this troublesome species- 

 stands in some respects intermediate in characters between the 



