81 
In view of existing descriptions and figures, (Cabot, ’72, p. 2, 
No. 2, Pl. L., Fig. 3; Hagen, ’85, p. 266) it will be necessary here 
to give only those nymphal characters which are distinctive. 
The nymph measures in length 38 mm.; abdomen, 26 mm.; 
hind femur, 7 mm.; width of abdomen S mm., of head 6 mm. 
Body flat, elongate, gracefully tapering posteriorly; surface 
but little hairy. 
Labium with median lobe of mentum rather prominent, a 
median apical tooth on its front margin, in the middle of the 
usual comb of flat spinous scales; lateral lobe with a blunt- 
pointed and incurved apical hook, and on the inner margin 
seven or eight long irregular teeth, widening apically, and 
obliquely truncate so as to appear to be directed backward. 
Abdomen lanceolate, attenuate to apex, slowly tapering for 
half its length, to the cylindrical 10th segment; a dorsal hook 
on segment 9, represented on other segments by obtuse ridge- 
like elevations ; lateral spines on segments 7 to 9, on 7 minute, 
on 8 short, on 9 long, closely appressed, nearly equaling the 
length of segment 10; superior and inferior appendages sub- 
equal, shorter than segment 10, laterals a little shorter than 
the others. 
Half-grown nymphs show clearly all these characters. 
14. Gomphus exilis Selys. 
In the Atlantic coast states from Maine to Maryland this 
species is often abundant. In Illinois the imago has been taken 
at Crystal Lake, about 40 miles northwest of Chicago, by Mr. 
Longley, and at Kensington by Mr. McDade. Williamson 
records a few examples from Indiana, and according to Kelli- 
cott it is common throughout Ohio, especially about canals and 
ponds. Hagen has described the nymph (’85, p. 263), and 
doubtfully referred to the same species some examples sent him 
from Kentucky. Dr. Calvert records it as the first gomphid to 
appear in spring (May 24), its season of flight lasting until the 
early part of July. The extreme recorded dates are May 9 
(Kellicott) and July 8 (Williamson). 
