SPINNING HABITS. 331 



the greater are its chances of being carried into new localities. 

 To learn the quantity of silk that one of these caterpillars 

 can spin, a reel was made and mounted in a frame. Cater- 

 pillars were taken on a soft brush and then jarred off into 

 space. This caused them to spin, when, by attaching the 

 end of the thread to the wheel and manipulating the cater- 

 pillars carefully, the silk was reeled off and a record kept of 

 the number of revolutions of the wheel, until the caterpillars 

 could not or would not spin. It was found that they spun 

 best when a slight current of air was blown upon them. In 

 this manner caterpillars of known ages were experimented 

 with. Many of these experiments gave only negative results, 

 for the manipulation necessary in getting the thread started 

 often disturbed them so that they would spin only a few feet. 

 The following results were obtained from a number of the 

 experiments : 



March 22 : Four caterpillars, just hatched, were taken be- 

 fore any of their store of silk had been drawn upon. The 

 first spun 4 feet and 6 inches, the second spun 9 feet and 1 

 inch, the third spun 38 feet and 2 inches, and the fourth spun 

 69 feet and 4 inches, a distance greater than the height of 

 an average shade tree. March 14 : Of five first-molt cater- 

 pillars, the first spun 53 feet and 2 inches, the second 24 

 feet and 2 inches, the third 3 feet and 2 inches, the fourth 6 

 feet and 4 inches and the fifth 7 feet. 



April 23 : Three more caterpillars, of the first molt, were 

 experimented with, and the following results obtained : the 

 first spun 25 feet and 3 inches, the second 22 feet and 6 

 inches and the third 47 feet and 9 inches. March 22 : Of 

 two second-molt caterpillars, the first spun 8 feet and the 

 second 2 feet. Other caterpillars, in the later molts, were 

 tried, but they could not be induced to spin. There seems 

 to be a decrease in spinning power as the caterpillar grows 

 older. Caterpillars of the second, third and fourth molt have 

 been seen spinning down to a considerable distance from trees 

 on which they were feeding, and in this manner they were 

 able to make the wind and passing teams aid them in finding 

 their way to suitable food plants. 



The last thing before entering upon the rest previous to 

 molting is the spinning of a number of threads, forming a 



