1298 THE BUTTERFLIES OF NEW ENGLAND. 



which it rests, is scarcely at all attached to the leaf in the centre, so that 

 its sleep is taken on a spring bed, as it were. It is formed of interlacing 

 threads which lie to some extent across the leaf, few or none being longi- 

 tudinal, though many are oblique. The carpet seems, however, to be 

 closely attached to the leaf both toward the stem and toward the apex of 

 the latter, but not quite so densely as at the sides, and the carpet has con- 

 siderable thickness. As Gosse says (Can. nat., 293) : — 



It spins a bed of silk so tightly stretched from one edge of a leaf to the other as to 

 bend it up, so that a section of it wonld represent a bow, the silk being the string. 

 On this elastic bed the larva reposes, the fore parts of the body drawn in so as to swell 

 out that part, on which the eye spots are very conspicuous. 



When reposing here, says D'Urban (Can. nat., v : 87), "these larvae, 

 if disturbed, rock themselves slowly from side to side, throwing out the 

 forked, orange tentacle, which is usually concealed from view in the seg- 

 ment beliind the head, emitting at the same time a very acrid odour." Mr. 

 L. Trouvelot (Proc. Bost. soc. nat. hist., xii : 92) gives the folloT\'ing lively 

 account : — 



Every one knows that this larva, when at rest, remains upon the middle of the upper 

 part of a leaf ; for this purpose a carpet of silk is spread npon the leaf by the larva. 

 This leaf, by means of the silk, is made to curve a little. On oue rainy morning I ob- 

 served one of these young larvae upon a lilac bush in my garden. I certainly thought 

 that the invention of resting iu the hollow of a curved leaf on a rainy day was a very 

 poor one, for since the bent leaf performed the office of a gutter, the water must flow 

 through this channel, the larva be inundated and inevitably drowned, if the rain lasted 

 but a few hours. I soon found that there were more brains in the small head than I 

 had supposed. The larva began to move ; it spun some silk from one edge of the leaf to 

 the other, and by adding many fibres to make it strong, each new fibre shorter than 

 the preceding, the leaf was soon made to curve more and more. I then began to 

 understand what this laborious work was for, and I thought that sometimes small 

 people might give lessons to larger ones. After about an hour the larva ceased to 

 work, a real bridge was built over the torrent, and upon it laid motionless and out of 

 danger the little larva. Would you call such an act instinct, or would you call it 

 reason? If you call it instinct, I would say that this instinct is very reasonable. 



I find the following in the late Dr. Asa Fitch's note books : — 



July 17, 1876. A young apple tree three feet high, set out last spring I discover is 

 defoliated by two of these larvae, now nearly grown, only a few fragments of green 

 foliage remaining. I place one on a similar newly set apple in full leaf. It immedi- 

 ately begins spinning a web from its mouth, upon a leaf, to enable it to cling to it. 

 The other I put on another similar apple tree, on which I notice ants are running up and 

 down, to some curled leaves at ends of the limbs, where they have Aphides, and any 

 of them coming to this larva, attack it, causing it to shrug spitefully to shake them 

 off. I chalk the body of the tree towards its base, to prevent them from ascending it, 

 and kill all the lice and ants from the curled leaves, and drench the ground at the base 

 of the tree with water, hoping to drown and drive the ants away. 



Next morning I find the first larva stationed on the leaf, holding securely thereto, 

 standing nearly upright upon the leaf, which the weight of its body inclines almost to 

 a perpendicular, and it is here being rocked by the leaf swinging in the wind, con- 

 stantly, the worm holding securely to it, and seeming to enjoy the rockiug excercise. 



The other larva has disappeared from the tree, which is populated by numerous 

 ants, which have worn a road for themselves through the chalk, and are thronging 



