114 SUPPLEMENT ON 



remarkable differences observed in the external forms of the 

 individuals which compose them, but still more by the insti- 

 tutions by which they are governed. Their principal end 

 is the education of the young, and even those which, under 

 the form of nymphae, have no further need of nourishment, 

 find active and vigilant sentinels to prevent or avert the dan- 

 gers by which they may be threatened. 



At the period when this education is finished, these associ- 

 ations present us with three sorts of perfect individuals in the 

 full enjoyment of all their faculties, males, females, and in- 

 dividuals of the latter sex, but unfit for reproduction. These 

 last have been designated as neuters, mules, workers, and 

 even soldiers, as among the termites. The denomination of 

 workers is frequently equivocal, since the females, in some 

 species, are equally industrious. Neuter appears to be 

 preferable. 



These societies are either temporary or continuous. When 

 temporary, they owe their origin to a female, who, without 

 assistants, abandoned to her own resources, lays the founda- 

 tions of the colony, and soon finds auxiliaries in the neuters 

 which she begins to bring into the world. Such are the soci- 

 eties of wasps and humble bees. But those which are conti- 

 nuous, have neuters at all periods. Sometime these neuters, 

 as among the ants and bees, are charged exclusively with all 

 the labours and cares of the family. Sometimes they have 

 no other functions than to watch for the defence of the com- 

 munity, and perhaps for the preservation of the germs of the 

 race, as among the termites. 



The countries situated between the tropics are those where 

 nature has most energy, and where these assemblages of 

 insects are most multiplied and most formidable. The action 

 exercised on animal and vegetable substances by insects, 

 which live in an isolated or solitary state, is usually slow, 

 and its effects are not sensible but in the course of a time. 



