AQUATIO INSECTS 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. posita, has been referred hitherto. 
Fig.12 Labia of Enallagma and Ischnura; a and pb, labium of E. signatum; 
cand d,of Il. 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 @& 
Mig is Hees of Lsechnura yerticalis 
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 
