48 Studies on Life-history of Bombycine Moths. 



writes me that his larvae occurred on the swamp oak. Though 

 belonging to the Psychidse, both in their larval structure, as well 

 as their cases, and the characters of the moths, the two American 

 genera Lacosoma and Perophora differ remarkably from the normal 

 members of the family. The larvae of both genera live upon the oak. 



In the present form the case is made by simply folding over one 

 oak leaf on each side of the midrib, so that it is flat, one edge being 

 thin, and the other full and thick. It is difficult to dislodge the 

 caterpillar from its roomy sack, and in this respect it is just the 

 reverse in its habits from the ordinary leaf-rollers ; this is perhaps 

 due to its heavy and highly modified bod}^ since if it had to leave 

 its case and drop to the earth, it would perish. Still it can readily 

 turn around within its roomy case. It is, as Riley states in his 

 brief description of the habits of Perophora mehheimerii, like the 

 latter "active and savage," as when I attempted to di-aw it out 

 of its case it would vigorously bite at the end of my forceps, an 

 unusual trait in caterpillars. On finally removing it from its case 

 without injury it was very sluggish and did not stir while I was 

 examining it. I put it back in the box in which it was sent, and 

 in the course of an hour it had found its case, and had sewed up 

 and mended the side of its case which I had to open in order to 

 draw it out without injuring it, as it promised to be a difficult task 

 to remove it without rupturing the body. 



The special and striking adaptation of this larva to its life in a 

 loose case, which shows that it, with Perophora, is a stem-form, 

 connecting the normal Psychidae with ordinary Bombycine cater- 

 pillars, is seen in the following points: — 



1. The obsolete dorsal lines and stripes of the middle of the 

 body, this portion not being occasionally exposed to the light, as 

 are the head- and tail-end. This plainly indicates the origin of this 

 form from a larva which may have fed on leaves, whose body was 

 continuously striped from head to tail, and which had the general 

 habits and mode of ornamentation of larvae, for example like those 

 of the PhycitiB, which are more or less chestnut-brown, striped with 

 darker, and which live among leaves or masses of their castings, 

 and which live partly shut up from the light. The cause, then, of 

 the atrophy of the normal markings is the absence of light. 



2. The small middle abdominal legs, which owe their reduction 

 in size to disuse. In this respect this larva connects the apodous 

 Psychid caterpillars with normal ones. 



