1890 .] 
531 
[Packard. 
humps of the eighth abdominal segment are more pronounced 
than in the earlier stages. The extensile, uplifted anal legs are 
black at the tips. 
Fourth stage , after third moult. — Aug. 10-11 . Length, 22-24 mm. 
In this stage the larva only differs from the preceding one in the 
deeper, more distinct colors of the body and its markings, while 
the body itself is larger and thicker. The black tubercles on the 
first abdominal segment are slightly smaller than before. 
Fifth stage , fully-fed larva. — Length, 55 mm. Differs from the 
fourth stage in the rather thicker body, slightly shorter anal legs, 
and the smaller first abdominal black dorsal tubercles ; while the 
black spots on the eighth abdominal segment are more pronounced. 
One found by Mr. Bridgham, Sept. 6, on the wild indigo. 
Recapitulation. — 1. The larva hatches with the generic charac- 
ters already established : viz., with the long slender retractile anal 
legs, unprovided with hooks, and with the pair of hairless dorsal 
tubercles on the first abdominal segment. 
2. The two dorsal tubercles on the eighth abdominal segment 
lose the hairs at the first moult and begin to assume the shape and 
coloration seen at the last stage. 
3. The glandular hairs disappear with the second moult. 
4. In the third stage the coloration and markings of the species 
begin to appear, the body changing from pea-green to straw-yellow, 
the skin smooth and shining, and the lines and spots blackish, 
while the reddish tint of the first abdominal segment, charac- 
teristic of the first stage, is discarded. 
It is probable, though further field work is needed to prove it, 
that by the third stage the caterpillar is exposed to the same dan- 
gers and escapes them in the same way as the larva in its final 
stage. Observations as to the position of the larva while feeding 
on the locust or wild indigo leaf are needed in order to show how 
the reddish head, shining straw-yellow body and blackish stripes 
and markings assimulate it to its habitat; also whether ichneumons 
are repelled by the movements of the anal legs, and whether such 
motions of the end of the body are sufficient to drive away ichneu- 
mons and Tachinae from its otherwise unprotected, smooth body. 
These remarks will also apply, though less strongly, to the cat- 
erpillar of Edema alb if rons, which has similar shape and coloration, 
though its anal legs are not retractile, nor so long and slender and 
hence not so well calculated to frighten away unwelcome insects. 
