40) 
The species are numerous and difficult of separation. The 
nymphs are not usually abundant, and as few of even the com- 
moner American species have been bred, our knowledge of the 
immature stages is as yet unusually imperfect. The key which 
follows indicates the salient characters of the nymphs here 
treated. In the young nymphs of #schna sp. ba tendency to 
abdominal cross-bands was noted, and the sutures beneath 
were broadly bordered with paler color, except those between 
3 and 4, 6 and 7, and 8 and 9. 7 
KEY TO THE NYMPHS OF ASCHNA HERE DESCRIBED. 
aa. Lateral spines of sixth abdominal well developed, reaching 
at least about half way to the hind margin of the seg- 
ment; those of seventh attaining about to the hind 
margin; lateral labial lobes squarely truncate at tip. 
bb. Fifth abdominal with minute lateral spines, lateral 
appendages fully two thirds as long as the superior 
appendage; supracoxal processes sharp, equal. 
1. clepsydra. 
b. Fifth abdominal with at most only a trace of lateral 
spines; lateral appendages less than two thirds as 
long as the superior; supracoxal processes less sharp, 
the posterior larger; abdomen in younger individ- 
uals with a medio-dorsal pale line bordered each 
side with blackish. 2. constricta. 
a. Lateral spines of sixth abdominal minute, distant from its 
hind margin by several times their own length, those 
of seventh reaching about half way to the hind margin. 
cc. Apices of lateral labial lobes squarely truncate, con- 
tiguous when closed; in younger specimens a pale 
spot near anterior ocellus and another on clypeus, 
and a pale median line enlarged on the middle 
of abdomen into an increasing series of pale spots, 
the largest and last on segment seven. 
dd. Superior appendage sparsely fringed laterally with 
pale hairs; posterior part of head with some pale 
