THE CANADIAN ENTOMOLOGIST. 63 



HINTS ON COLLECTING COCOONS OF THE LUNA 



MOTH — Tropcea I una. 



BY ROBERT BUNKER. 



Many Entomologists are under the impression that the cocoons of 

 this species and polyphonies are exactly alike in appearance. This is a 

 mistake ; and the collector who has been misled by writers on the subject 

 and has got together by careful searching a dozen cocoons, expecting at 

 least to get a small share of lunas from them, is greatly disappointed 

 when they change to find them all polyphemus. 



Having had some experience in collecting cocoons of both species, I 

 will endeavor to point out the differences. The polyphe?nus cocoons are 

 white, or dirty white, 1.25 to 1.75 in. long (those producing females the 

 largest), with rounded ends ; sometimes angular, caused by leaves being 

 moulded unevenly to the surface ; generally coated with white powder ; 

 firm in texture, and producing silk of a coarse quality. 



The lima cocoons are chestnut brown, a little larger than polyphemus ; 

 egg shaped ; very thin, and frequently rough on the surface, covered with 

 warts and excrescences ; they seldom show the print of leaves on their 

 surface. 



From my own observations, I am strongly inclined to the opinion that 

 the larva of this fair queen of the night seldom spins its cocoon between 

 leaves in the tree, but crawls to the ground and fastens it to any object 

 that comes in its way. This belief has been strengthened by frequently 

 finding cocoons with grass moulded to their surface ; furthermore, last 

 fall I found a cocoon firmly attached to a tuft of grass six or eight inches 

 from the ground, and another fastened to a twig or sucker about the same 

 distance from the ground ; add to the above the fact that cocoons are 

 almost always found on the ground near the trunk of the tree, and we 

 have a pretty clear case that the habits of this elegant species are quite 

 different from those of polyphemus. 



Hickory, Beech and Oak are the food plants of this species ; poly- 

 phemus has a much wider range, and is, consequently, far more numerous. 

 In collecting I find about six of the latter to one of the former. 



Spring is the best time to search for cocoons, as most of the leaves 

 blow away during the winter, leaving the cocoons exposed to view ; it is 

 best, however, to look for them both in fall and spring. 



