86 NATURE STUDY REVIEW [9 :3— Mar., 1913 



Other kindred trees throughout the summer, although I have 

 found them most numerous early in September, when the cater- 

 pillars are about grown and the cocoon-like nests quite con- 

 spicuous. 



The Mocha-stone moth deposits her eggs in a mat-shaped 

 group, and when these hatch the little crawlers draw the edges 

 of the leaf on which they chance to be born together and snuggle 

 down within, eating the green tissue of the leaf until lack of 

 food forces them to add a second leaf to the first, or, more fre- 

 quently, they migrate to a larger leaf. This leaf they line with 

 silk and web together in such a way that it forms an oval room 

 which at first glance appears not unlike the cocoon of a big silk- 

 spinning caterpillar known as Telea polyphemus, but its walls 

 are not so dense and the silk is more like that spun by spiders. 

 The resemblance is intensified by the fact that the Mocha-stones 

 carry the threads from the lining of the leaf around and around 

 its petiole and then they fasten these about the parent twig, much 

 as do some of the polyphemus larvae. 



The shape of the leaf when rolled is such that there seems 

 always to be an open space at the upper end of the cocoon. Ap- 

 parently the caterpillars realize that a bird which had discovered 

 their whereabouts could secure each and every one of them 

 through this opening much more easily than it could if the open- 

 ing were closed, for we find in the nests of the grown larvae, at 

 least, a piece of densely spun silk stretched across the opening 

 and fastened to its edge, but in such a way that a round hole 

 is left at the side of the petiole, and through this the caterpillars 

 go to and return from their feeding gounds. 



The doorway is too small to allow more than a single 

 larva at a time to pass, and it is amusing to see how one will 

 poke out its head as if reconnoitering, then, if the road is clear, 

 it will crawl up the stem to a leaf and begin to eat. Occasionally, 

 however, two individuals meet at the threshold, but when this 

 •occurs there seems never to be any caterpillar controversy as to 

 which shall go first. One or the other yields its place instantly 

 and waits his opportunity. 



Such a meeting occurred between the larvae shown in the 

 illustration. The returning caterpillar in this instance crawled to 

 the side of the nest and remained there until his fellow had 

 passed out and left the opening free for him to enter. 



Now, have these Mocha-stone larvae a vague notion that a 

 squabble over their rights might attract the attention of bird 

 enemies, or are they instinctively the Gastons and Alphonsos of 

 the caterpillar world? 



