OF NATURAL HISTORY. 427 



this country, they feldotn go out of the neft till the middle or end 

 of April. When they ftiut themfelves up for the winter, they are 

 very fmall ; but, after they have fed for fome days in fpring upon 

 the young and tender leaves, they find the neft iifelf, and all the en- 

 trances to it, too fmall for the increafed fize of their bodies. To re- 

 medy this inconveniency, thefe difgufting reptiles know how to en- 

 large both the neft and its paflages by additional operations accom- 

 modated to their prefent ftate. Into thefe new lodgings they retire 

 when they want to repofe, to fcreen themfelves from the injuries of 

 the weather, or to caft their Ikins. In fine, after cafting their fkins 

 feveral times, the time of their difperfion arrives. From the begin- 

 ning to near the end of June, they lead a folitary life. Their focial 

 difpofition is no longer felt. Each of them fpins a pod of coarfe 

 browniili filk. In a few days they are changed into chryfalids ; and, 

 in eighteen or twenty days more, they are transformed into butter- 

 iHies. 



Caterpillars of another fpecies, which Reaumur diftinguifties by 

 the appellation oi the proceffionary caterpillar, live in fociety till their 

 transformation into flies. Thefe caterpillars are of the hairy kind, 

 and are of a reddifti colour. They inhabit the oak, and feed upon 

 its leaves. When very young, they have no fixed or general habi- 

 tation. But, after they have acquired about one half of their natu- 

 ral fize, they afl"emble together, and conftrudt a neft fufficient to ac- 

 commodate the whole. The nefts of thefe caterpillars are attached 

 to the trunks of the oak, and are fituated fometimes near the earth, 

 and fometimes feven or eight feet above its furface. They confift 

 of different ftrata, or layers, of filk, which are fpun by the united la- 

 bour of the whole community. Their figure is neither ftriking nor 

 uniform. On the part of the oak to which they are fixed they form 

 a protuberance fimilar to thofe knots which are feen upon trees. 

 This protuberance fometimes refembles a fegment of a circle, and 



3 H 2 fometimes 



b 



