184 AFPLE-TREE CATERPILLAR — LEAVES WHICH IT EATS. 



But this insect is not entirely limited to trees of the cherry 

 and apple kind. I have seen its eggs placed upon the witch 

 hazel (Hamamelis), and the caterpillars from them when nearly 

 mature, appeared as thrifty and well fed as those upon the apple 

 trees. Three small nests, each containing about two dozen 

 worms, were once seen upon a small beach tree. On willows 

 numbers of these caterpillars may be seen every year, when they 

 are nearly mature; and on tieing a cherry twig, containing a 

 nest of worms but two or three days old, to the limb of a yellow 

 willow, they were found to grow as thriftily as those in other sit- 

 uations. The poplars, at least our indigenous species, appear to 

 be equally congenial to them. And the white oak, the leaves of 

 which are small and tender when the caterpillars are nearly full 

 grown, they feed upon freely. The black or quercitron oak 

 seems unadapted to them. The young worms of a nest tied to 

 this tree languished and after a time all died; a nest of half 

 grown worms ceased to advance further in size, and finally the 

 more robust individuals appeared to have abandoned the tree, 

 and the remainder perished. Nests of worms when half grown 

 were placed upon the lilac, the syringa (Pkiladelphus coronarius) 

 and the striped dogwood (Viburnum Acerifolium). In each of 

 these instances the nests were forsaken by the worms within a 

 day or two. A nest of worms newly hatched and too young to 

 migrate elsewhere, was placed upon the garden currant, and 

 another upon the alder (Alnus). In each of these instances the 

 worms sustained themselves upon the leaves but made scarcely 

 any advancement. When the caterpillars on other trees were 

 mature these had not attained a third their size. They however 

 all continued in their nests, feeding slightly upon the foliage 

 around them, until the period for spinning their cocoons had 

 nearly expired. They then suddenly dispersed themselves and 

 probably all perished, being too small and weak to construct 

 their cocoons. The fact shows that animal life may for a long 

 time be sustained upon food which is so unpalatable and so lit- 

 tle nutritious to the individual that no growth or development 

 can take place. 



Like other insects, this is much more numerous in particular 

 years. This fact has been noticed from the earliest times. We 



