428 THE PHILOSOPHY 



{ometlmes it is three or four times longer than it is broad. Some 

 of thefe nefts are from eighteen to twenty inches long, and from five 

 to fix inches wide. About the middle of their convexity, they oftea 

 rife more than four inches above the furface of the tree. Between 

 the trunk of the tree and the layers of filk a fmgle hole is left, to 

 allow the animals to go out in queft of food, and to retire into the 

 neft after they are fatiated. Notwithftanding the great bulk of thefe 

 nefts, and though there are often three or four of them upon the 

 fame tree, and never elevated above the height of diftind vifion, they 

 are not eafily perceived j for the filk of which they are compofed is 

 cinereous, and refembles, in colour, thofe raoffes with which the 

 trunk of the oak is generally covered. 



The inhabitants of a neft, which are numerous, march out, about 

 the fetting of the fun, to forage, under the condud of a chief or 

 leader, all whofe movements they uniformly follow. The order 

 they obferve is fingular. The firft rank confifts of fingle animals, 

 the fecond of two, the third of three, the fourth of four, and fome- 

 times more. In this manner they proceed in queft of food with all 

 the regularity of difciplined troops. The chief or leader has no 

 marks of pre-eminence; for any individual that happens firft to 

 iflue from the neft, from that circumftance alone, becomes the lead- 

 er of an expedition. After making a full repaft upon the neigh- 

 bouring leaves, they return to the neft in the fame regular order; 

 and this prailice they continue during the whole period of their ex- 

 iftence in the caterpillar ftate. It was from this ftrange regularity 

 of movement that Reaumur, with much propriety, denominated 

 thefe animals proceffionary caterpillars. When arrived at maturity,, 

 each individual fpins a filken pod, is converted into a chryfalis,. 

 and afterwards aflumes the form of a butterfly. This laft tranf- 

 &rmation breaks all the bonds of their former aSbciation, and the 



femalcL 



