122 QUINCE CULTURE. 



tended to three inches, as it often is in traveling, the 

 thickness is greatly reduced. 



The worm moults four times, at intervals of ten days, 

 and then a fifth time after twenty days. Soon after the 

 last moult it draws a few leaves together, within which 

 it spins a short, thick cocoon of pure silk. In confine- 

 ment I have found it spins enough of its cocoon in a 

 single night to entirely hide itself ; but it evidently con- 

 tinues to spin much longer on the inside, as its motions 

 indicate. Like all its congeners, it spins a double thread 

 from its mouth, gumming it enough to make it strongly 

 adhesive, not only to all points of attachment, but to all 

 parallel and intersecting threads. When finished it is 



Fig. 110. COCOON OF THE POLYPHEMUS MOTH. 



water-proof. It pupates soon after the cocoon is com- 

 plete, and in about twenty days the moths of the first 

 brood appear. 



The twelve segments of the larva are each marked 

 with three side rows of very bright yellow spots. The 

 seven segments in front of the posterior also have a 

 very bright line or bar, slightly inclined forward, and 

 reaching from the dot of the upper row to that of the 

 lower row, and passing the dot of the middle row. On 

 the back is a row of small hairy elevations, one on the 

 top of each segment. The head is pale brown, the spi- 

 racles pale orange, and the V-shaped band around the 

 tail is a purplish brown. The feet of the first three seg- 

 ments are sharp claws ; the next two segments are foot- 



