50 N.S. ENTOMOLOGICAL SOCIETY. 



vae do not feed on the shell of the egg from which they have just emerged, as is cus- 

 tomary with manj/ Lepidopterous larvae, but at once start feeding on the pulp of the 

 tender foliage until finally the whole leaf is skeletonized, so that in serious infestations 

 the trees have the appearance of being swept by fire. It is characteristic of the larvae 

 in all stages when disturbed to drop by a silken thread and in most cases stay suspended 

 in tne air; then, when danger is past, they draw themselves up by means of this thread 

 and resume their feeding. The larvae pass through a series of five moults, the last molt 

 taking place after the earthen cocoon has been made. As a rule they stop feeding a 

 short time previous to moulting and have a contracted appearance. Trie canker worms 

 are ravenous feeders throughout their larval stages, feeding extensively by night, as well 

 as in the day. The larva has three pairs of prolegs, the first pair being smaller and not 

 used when the caterpillar loops or spans in walking. 



DESCRIPTION OF INSTARS. 



First Instar. — Length when first hatched 1.27mm.-2.02 mm. Head, .35 mm.-. 37 m 

 m. wide, whitish yellow in color, bearing a few short white setae. Prothoracic shield 

 slightly darl er tnan head. Two rows of small tubercles occur longitudinally over the 

 dorsum, one pair to each segment. General body color, grayish white. Thoracic legs 

 concolorous with the body. 



Second Instar. — Length after moulting 3.8 mm.-4.5 mm. Head .43 mm-. 48 mm. 

 wide, of a greenish color. Prothoracic shield concolorous with head. Small tubercles up- 

 on dorsum beset with minute setae. General coloring and markings similar to previous 

 instar. 



Third instar. — Length when newly molted 6.0 mm. -8.0 mm. Head .525 mm. 

 .62 mm. wide; yellowish green in color, bearing a few short white setae. Two broken 

 whitish stripes run longitudinally over the dorsum, also two similar lateral whitish 

 stripes rather more broken. Spiracles ringed with brown. The dorsal tubercles occur- 

 ring in previous instar have almost entirely disappeared. Thoracic legs and prolegs 

 concolorous with the body. Anal plate beset with short white setae. 



Fourth instar. — Length after moulting 9.5 mm.-10.2 mm. Head 1.0 mm.-1.18 

 mm. wide, beset with fine setae. Color green to dark brown. Prothoracic shield con- 

 colorous with head. A broad stripe runs longitudinally over the dorsum, green to 

 brown or black. Three lateral stripes occur on either side, the one nearest the dorsal 

 stripe greenish in color, the following two concolorous with the dorsal stripe. 

 All stripes are divided by a narrow white line. Ventral surface thoracic legs and 

 prolegs light green. Scattering setae on anal plate. General body color green to brown 

 or black. 



