430 THE PHILOSOPHY 



covered with filk. In this, as well as In many other inftances, Na- 

 ture obliges animals to embrace the mofl effedual means of felf-pre- 

 fervatlon, and even of conveniency, without their perceiving the 

 utility of their own operations. The caterpillars, whofe manners 

 we have been defcribing, fpin almoft continually, becaufe they are 

 continually obliged to evacuate a filky matter, fecreted from their 

 food by veflels deftined for that purpofe, and included in their in- 

 teftines. In obeying this call of Nature, they effe£tually fecure their 

 retreat to their nefts, and perhaps their exiftence. It may be faid, 

 that caterpillars aflbciate for no other reafon but becaufe they are all 

 produced at the fame time from eggs depofited near each other. But 

 many other fpecies of caterpillars, who are brought to life in the 

 very fame circumftances, never affociate or afl; in concert in the per- 

 formance of any mutual labour. The filk-worms afford a familiar 

 example. It is true, they fpontaneoufly remain aflembled in the 

 fame place, which is of great advantage to manufadure. But the 

 individuals of other fpecies difperfe immediately after birth, and ne- 

 ver re-unite. Spiders, when newly hatched, begin with fpinning a 

 web in common ; but they foon terminate this aflbciation by de- 

 vouring one another. 



As caterpillars do not engender till they arrive at the butterfly 

 ftate, their aflbciations have no refped to the rearing or education of 

 young. Self-prefervation and individual conveniency are the only 

 bonds of their union. A perfedt equality reigns among them, with- 

 out any diftindion of fex, or even of fize. Each takes his fhare of 

 the common labour; and the whole fociety, which conftitutes but one 

 family, is the genuine iflue of the fame mother. 



The affociation and oeconomy of the common ants merit fome 

 attention. With wonderful induftry and adtivity they colledt mate- 

 rials for the conftrudion of their neft. They unite in numbers, and 



affift 



