MEMIOKS OF THE ]S"ATIONAL ACADEMY OF SCIEjSXES. 
35 
recapitulated tlie congenital characters, and finally given a synopsis of the chief steps in the 
evolution of the adaptional characters, which appear after the first exuviation. It seems very 
probable that these later features were the result of the action of external stimuli, both physical 
and biological, and that they were ac(iuired not only during the lifetime of the larva, but at certain 
distinct stages or periods during the growth of the creature. The changes are both colorational 
and structural, and during the different stages the larva was adapted Ibr different surroundings,, 
aud thus at each important stage was virtually for the time being a distinct animal. 
During the pupa stage st»ecial and unusual structural adaptations arose, the cremaster being 
unusually developed, and also a pair of cephalic hooks, seeming to entangle the head in the web 
of the cocoon, so that the pupa can not be thrown out of the curled leaf, which remains in the first 
brood on the trees. These 1 regard as characters acquired by the insect after birth and in response 
to the exigencies of life at different stages. I will here add the conclusions given in th.at papeiv 
RECAPITULA.TION OF THE SALIENT FEATURES IN THE ONTOGENY OF DREPANA ARCUATA. 
A. CONGENITAL CHARACTERS OF THE LARVA. 
1. Anal legs obsolete; suranal plate already ending in an elevated rod-like spine in Stage L 
2. Glandular hairs (split at the end) present only in Stage 1. 
3. Piliferous warts well developed but of uniform size on all the segments in Stage I. 
4. Head aud body dark bi’own, but the warts pale; uromeres 1 and 7, pale yellowish in 
Stage I. 
5. Crochets of abdominal legs more numerous than usual, forming an incomplete circle,, 
compensating for the lack of anal legs and crochets. 
0. These congenital characters are of generic value, the specific characters appearing at and 
after Stage HI. 
B. EVOLUTION OF LATER ADAPTATIONAL CHARACTERS. 
1. Eeductiou in size and length of hairs after Stage I, glandular hairs being replaced by 
ordinary tapering ones. 
2. At the beginning of Stage III the body becomes yellowish-green, and the dorsal regioif,. 
previously dark, becomes broken up into pale yellowish-green spots. Head distinctly banded 
with yellow. 
3. In Stages lY and Y the greenish portions of the body become darker, like that of the food 
plant, and the reddish-brown parts are assimilated to the hue of the leaf stalks and twigs. 
4. In Stage III the prothoracic dorsal warts degenerate, and those of the two succeeding 
stages slightly progress in development. 
5. The ninth. uromere becomes as large as, if not slightly larger than, the eighth, and separated 
by a distinct suture-from the tenth — a very unusual feature in caterpillars. 
0. The chief adaptational features are: (I) colorational, to enable the partly or fully grown 
caterpillar to escape observation, and (2) structural, the unusually large ninth and tenth abdom- 
inal segments being upraised, with the upturned threatening suranal rod or spine litted to frighten 
away ichneumons or Tachime, and possibly insectivorous birds, 
C. A SPECIAL .ADAPTATION IN THE PUPA. 
The pair of cephalic stout hooks serving to entangle the head in the web of the cocoon, the 
cremaster also being unusually well developed, so that the pupa, which in the first brood remains 
on the tree, is slung by its head and tail, and can not be thrown out of the curled leaf. 
D. PROTECTIVE COLORATION OK THE ^lOTH. 
When I first noticed the moths, with their broad wings outspread aud resting on the upper side- 
of the leaves, I mistook them for pieces of dead, dry, yellowish leaves which had fallen upon and 
become fastened to the surface of the fresh leaf. 
