AQUATIC INSECTS IN NEW YORK STATE 249 
tal setae four each side, lateral setae five (in one case six); end 
hook stout, arcuate, short, above which, on the distal margin 
of the lateral lobe and separated from the hook by a deep notch, 
are five minute teeth decreasing in size externally. Thorax 
narrower than head, wing cases reaching the base of segment 
5 of abdomen; segments of the abdomen short, somewhat taper- 
ing to apex. Gills [pl.15, c] more than half as long as abdomen, 
lanceoval, widest in the middle, the superior border more convex 
than the inferior specially in the two lateral gill plates. 
NEHALLENNIA 
Two delicate bronzy green species are included in our fauna. 
One is widely distributed and well known; the other has not 
been hitherto reported from the State. These are among the 
most highly specialized of the Agrioninae, as evidenced by the 
reduced wing venation, the skewness of the thorax, the slender- 
ness of the body, and the color. Reedy places in still water, 
specially places of springs and bogs, are their favorite haunts. 
I have bred our common species N. irene, and describe its 
nymph below; the nymph of N. gracilis is unknown. The 
imagos may be distinguished as follows: 
a Apex of the abdomen of the male with bronzy green lateral 
triangles laid on the blue of segments 8-10; hind margin 
Cmproriorax Of female trilobed.......... 0.2.00 .es nese eens irene 
aa Apex of abdomen of male all blue on segments 9 and 10, 
and on segment 8 except a narrow basal ring; hind mar- 
Emcor prothorax of female bilobed.......cccccesnngecnes gracilis 
Nehallennia irene Hagen 
Plate 18, fig. 4, 5 
1861 Agrion irene Hagen, Synopsis Neur. N. Am. p.74 
1876 Nehallennia irene Selys, Acad. Belg. Bul. (2) 41:1240 
1898 Nehallennia irene Calvert, Am. Ent. Soc. Trans. 20:234 
1895 Nehallennia irene Calvert, N. Y. Ent. Soc. Jour. 3:43 (listed 
from Ithaca) 
1899 Nehallennia irene Kellicott, Odon. Ohio, p.29 
1900 Nehallennia irene Williamson, Dragon Flies Ind. p.265 
This species is common about swales, springs and bogs in shal- 
low reedy waters, associated with the bronzy green species of 
the genus Lestes, which dwell in the same situations. It is ex- 
ceedingly common at Lake Forest Ill., where I bred a number 
of specimens June 7 and 8, 1899. 
