174 Hx\LF HOURS WITH rN"SECTS. [Packard. 



seems to attempt to remove them. The loss of the leaves 

 does not kill the trees, but prevents the growth of any 

 apples. When these canker worms are fully grown, i.e., 

 about four or five weeks after they are hatched, between the 

 17th and 27th of June about Boston, they will be found to 

 vary exceedingly in color, some individuals being blackish, 

 others greenish-yellow. The average style of coloration is 

 an ash color on the back, beneath yellowish, with a black 

 stripe on the sides. It has a less number of feet than 

 most caterpillars, which gives it a halting, looping gait, as 

 if carefully measuring the ground over which it is walking ; 

 hence the name geometer. Deserting its tree top it either 

 creeps down tlie trunk of the tree, or lets itself down after 

 the manner of most caterpillars by means of a silken thread 

 spun from a little opening in its under lip. It doesn't wan- 

 der about, but immediately burrows from two to six inches 

 in the loose soil under the tree, and then forms a rude loose 

 earthen cocoon, fastening the particles of dirt together with 

 silk. Twent^^-four hours after the cocoon is finished the 

 worm changes to a chrj^salis, which is rather pointed in front 

 and light brown in color. Here the insect remains until 

 after the October frosts, when on warm days between the 

 cold snaps late in October, and in November and December, 

 and even in some exception all}'- warm days during the rest 

 of the winter, the adult insects come forth. 



Nature has endowed the sexes quite difierentl}' ; the male 

 is winged and flies about in a modest Quaker garb of gray, 

 fluttering with broad weak wings about the trunks of the 

 trees and paying court to the grub-like wingless females, 

 which are less flighty than their mates. A larger propor- 

 tion of individuals appear in the spring than winter. This 

 provision of nature that a part of the brood shall appear in 

 the autumn and a part in the spring ensures the life of the 

 species, since if it were not represented in part by the eggs 

 and clnysalides, a severe winter might destroy the latter, 



14 



