806 Journal of Agricultural Research vol. vi, no. 21 



claspers to whatever it is resting upon, usually a rigid object rather than 

 the foliage. In some cases — for more than 14 hours in the third instar, 

 21 hours in the fourth instar, and 56 hours in the fifth instar — before the 

 molt occurs, the apparent movement of the ocelli may be observed from 

 their normal position to a position entirely behind the mask and within 

 the stretched integument of the first thoracic segment. .Before the rup- 

 ture of the integument takes place, the old mask is in the position of a 

 muzzle in relation to the withdrawn head. The mask separates from the 

 body integument, which splits along the median dorsal line for perhaps 

 four segments. The larva moves its head vigorously from side to side and 

 brushes the mask off against some object or its own body. The with- 

 drawal of the body from the integument begins with the muscular action 

 of the body, the larva ultimately crawling forward a distance about one- 

 fourth or one-half its length, and after resting thus for a time if undis- 

 turbed, it will almost always turn around and eat its newly molted skin. 

 In no instance was a mask observed to be eaten. Immediately after 

 molting, the head and anal segments are white, the body and cast skin 

 moist, and the head noticeably larger in diameter than the body. 



One larva was observed to eat its cast skin in four to four and one-fourth 

 minutes. Another, which required only three minutes, held the cast skin 

 with the front pair of legs, remaining stationary and pulling the skin to it, 

 using the second pair of legs to hold to the foliage for the first minute and 

 utilizing them to help manipulate the partly eaten skin. Another, in the 

 third instar, took eight and one-half minutes to eat all but a trace of its 

 freshly cast skin. It used its front legs almost continuously and the 

 second pair of legs about half the time in holding the skin while eating it. 

 Another had occupied about five minutes in this process when it was acci- 

 dentally interrupted. 



When the mature larva has finished feeding, the alimentary tract is soon 

 emptied and shortens up to a marked degree, the larva then preparing to 

 spin a thin cocoon. In nature the larva burrows into the ground or 

 among or under trash. In the cages soil was supplied to some; others 

 had only the paper on which they were lying, others were among corn 

 foliage, and some had nothing whatever to utilize for a cell. In those 

 instances where soil was supplied, the larva spun an appreciable quantity 

 of silk as lining for its cell. Where paper was cut, the effort was appre- 

 ciable, but not enough silk was used to form more than a shallow cup. 

 Where there was foliage, it was chewed up and mixed with silk, but with 

 scant resemblance to a cocoon; where no material was furnished, the 

 silk was not evident, although pupation and the issuance of- adults 

 seemed to be equally normal. 



Just before pupation a deep pit develops in the emargination of the 

 posterior dorsal line of the mask, and transverse ridges on the dorsal 

 portion of abdominal segments 5, 6, and 7 show distinctly through the 

 larval skin. These ridges, interrupted at the ends, are marked with 20 



