144 



THE AMERICAN ENTOMOLOGIST. 



of Tenc-makiug Caterpillars, and cliiring the 

 first two or three days of their existence they 

 commence constructing a sheltei" for themselves 

 by extending sheets of web across the nearest 

 fork in the twig upon which thej^ were hatched. 

 As they increase iu size they construct addi- 

 tional layers over those previously made, at- 

 taching them to the neighboring twigs, and 

 leaving space enough between them for the 

 caterpillars to pass. The shape of the tent is 

 necessarily very irregular, depending upon the 

 situation of the branches upon which it is con- 

 structed. The holes through which the cater- 

 pillars enter are situated uear the extremities 

 or angles of the nest. This uest when completed 

 is about eight or ten inches iu diameter. The 

 caterpillars retreat into it at night and in stormy 

 weather, and at other times when they are 

 not feeding. The silken threads of which 

 the web is composed are di'awu from the body 

 of the insect through a minute aperture situ- 

 ated behind the mouth, which is the outlet of 

 two convoluted tubes, into which the ductile 

 matter is secreted from whicli the silk is made. 

 When going out to feed, the caterpillars always 

 travel upon the upper side of the branches, and 

 each one leaves a thread of silk behind it, which 

 probably serves as a clue to direct it back to the 

 nest. The silken trails thus formed are at first 

 scarcely noticeable, but become very obvious 

 after a branch has been traveled upon for a 

 considerable time. Thus the caterpillar not 

 only lives in a silken house, bu.t covers its roads 

 with a silken carpet. Like other larvre, they 

 shed their skins four times before arriving at 

 maturity. Wheu fully grown they arc about 

 one inch and three-quarters in length ; but as 

 they are widely known and easily recognized, 

 I shall not here occupy space by describing 

 them. 



The eyes of this caterpiller have the appear- 

 ance of very minute black points, being ten in 

 number, five on each side of the head. Their 

 position is best seen by holding the cast-otTskin 

 of a caterpillar towards the light, and examin- 

 ing it through a magnifying glass. Without 

 claiming mathematical exactness, it may be 

 stated that four of them are situated in a curved 

 line, forming half a circle, of which circle the 

 fifth occupies the centre. Owing to the extreme 

 minuteness of the eyes of caterpillars in general, 

 they were formerly overlooked, and these in- 

 sects were supposed to be blind. That they pos- 

 sess the sense of seeing, however, and that, too, 

 at a considerable distance, seems to be proved 

 by the following experiments. If a uest of these 

 caterpillars be taken from a tree and placed 



upon the ground several feet from it, they will 

 return to it in a direct line. In another experi- 

 ment a handful of caterpillars was placed in 

 some tall grass between two trees, but nearer 

 to one than the other. They first crept up the 

 stems of the grass, as if for the purpose of taking 

 an observation, and then took up their march 

 for the nearest tree. 



The leaves of the Apple tree constitute the 

 food of by far the greater number of this kind 

 of caterpillar. Nests are, however, occasion- 

 ally seen on the other common fruit trees, the 

 Peach, Pear, Plum, and Cherry, particularly 

 the Wild Cherry. When deprived of other food 

 they will also eat the leaves of the Rose bush. 



The active period of this caterpillar, that is, 

 the lime from their hatching to their changing 

 into chysalids, is from five to six weeks, and 

 when we consider their voracious appetites and 

 that there are about two hundred and fifty 

 individuals in each nest, we can easily form an 

 idea of the extent of their ravages. Where 

 there happen to be several nests on one tree, or 

 where the tree itself is small, they often strip 

 it of every vestige of foliage ; and in neglected 

 localities, whole orchards are sometimes seen 

 as bare of foliage on the first of June as in 

 mid-winter. It is at about this date that the 

 caterpillars cease their ravages, and the trees 

 subsequently make an effort to recover, and do 

 actually throw out a new set of leaves, but their 

 fruitfulness for the season is destroyed, and the 

 tree itself must have received a severe shock to 

 its constitution. 



After five or six weeks of voracious feeding, 

 the caterpillars ari'ive at maturity, and then 

 leave the trees, and are to be seen crawling in 

 all directions upon the neighboring fences or 

 other objects, in search of some suitable place 

 in which to undergo their transformation into 

 pupa?. They usually select some crevice or 

 angle where they can get an attachment for 

 their cocoons iu two directions. Their favorite 

 place is in the angle formed by the projection 

 of the cap-board of fences or posts. In these 

 positions they sometimes congregate so as to lie 

 one upon another. When about to construct its 

 cocoon, the insect attaclies itself by its hinder- 

 most feet, so as to leave the anterior part of its 

 body free for motion ; then extending its body, 

 it draws some disconnected lines across from 

 one side of the angle to the other, to serve as 

 outlines or stays. Then, working down nearer 

 home, it draws its lines more densely so that 

 near its body they constitute a pretty close 

 texture, like a piece of loosely woven cloth, 

 through which, however, the insect can be seen. 



