THE CANKER-WORM. 465 



hours afterwards, they are changed to chrysalids (Fig. 233) 

 in their cells. 



The chrysalis is of a light-brown color, and Fig 233 

 varies in size according to the sex of the insect <gg^ 

 contained in it ; that of the female being the lar- 

 gest, and being destitute of a covering for wings, which is 

 found in the chrysalis of the males. The occurrence of 

 mild weather after a severe frost stimulates some of these 

 insects to burst their chrysalis skins and come forth in 

 the perfected state ; and this last transformation, as before 

 stated, may take place in the autumn, or in the course of 

 the winter, as well as in the spring ; it is also retarded, in 

 some individuals, for a year or more beyond the usual time. 

 They come out of the ground mostly in the night, when 

 they may be seen struggling through the grass as far as 

 the limbs extend from the body of the trees under which 

 they had been buried. As the females are destitute of 

 wings, they are not able to wander far from the trees upon 

 which they have lived in the caterpillar state. Canker- 

 worms are therefore naturally confined to a very limited 

 space, from which they spread year after year. Accident, 

 however, will often carry them far from their native haunts, 

 and in this way, probably, they have extended to places 

 remote from each other. Where they have become estab- 

 lished, and have been neglected, their ravages are often 

 very great. In the early part of the season, the canker- 

 worms do not attract much attention ; but it is in June, 

 when they become extremely voracious, that the mischief 

 they have done is rendered apparent, when we have before 

 us the melancholy sight of the foliage of our fruit-trees and 

 of our noble elms 25 reduced to withered and lifeless shreds, 

 and whole orchards looking as if they had been suddenly 

 scorched with fire. 



[25 The insect which ravages the foliage of our "noble elm" in the South is the 

 larva of a beetle, Galeruca calmariensis, and hence the precautions here recom- 

 mended are inapplicable. The female flies upon the leaves to deposit her eggs, 

 59 



