248 CANKER-WORM. 



being larger than the previous one. The number of 

 these, and the time intervening, is not ascertained. 

 As they pass through these stages they become more 

 and more voracious, and in the last stage are more 

 destructive than in the whole of their previous exist- 

 ence, and make no hesitation in destroying the entire 

 foliage, but eat the green fruit. 



These worms spin a continuous thread as they move 

 about, and leave it attached to their path ; hence, if a 

 branch of the tree is struck so as to give it a sudden 

 shock, the worms may be seen suspended beneath by 

 this silken cord ; and when the shock has ceased, they 

 ascend to the place from whence they fell. Imme- 

 diately beneath the mouth, there is a conical papilla, 

 from whence the fibre that suspends them is emitted. 

 Their ascent, when thrown from the tree, is slow, and 

 is performed by bending the head and anterior part of 

 the body back, until the feet in the third segment can 

 grasp the thread with their jaws, thus continuing to 

 fold it up until they reach the branch of the tree. 

 They pause at intervals, if the ascent is long. If by 

 chance the thread should get broken, they crawl to the 

 trunk of the tree and ascend. 



The larva, or caterpillar, is, when full grown, about 

 one tenth of an inch in diameter ; the head pale, 

 marked on each side with two transverse, blackish 

 stripes ; the back ash-colored, marked lengthwise with 

 small, interrupted, dusky lines ; the side blackish, with 

 a pale line along the length of the body. There are 

 two white spots upon the last segment of the body. 

 The abdomen, or under side, is ash-colored. In 

 moving about, they draw up the hinder part to the 

 breast, bending the body into the form of the letter n; 

 then extending the body to take a new grasp with the 

 anterior feet, thus appearing to measure the space over 

 which they pass. From this circumstance they are 

 called geomatia, and in English, lopers, span-worms, 

 inch-worms, &c. 



