266 MENTAL FACULTIES sec. 



their own species or of their foster-parents which they find 

 in the appropriated nests. They drop also many eggs on the 

 bare ground, wliicli are thus wasted. But I should think 

 that tlie habits of this species perhaps indicate rather a de- 

 generation of the parasitic instinct than a higlier development 

 of it in comparison with tlie preceding species. The bird 

 seems beginning to make less careful provision for its eggs. 

 A third species, the Isl. pecoris, behaves exactly like our 

 cuckoo. Now, it is an important fact in relation to my view 

 of the evolution of the cuckoo's instinct that the M. pecoris 

 also is polygamous, and this seems also true of j\I. badius. 

 Mr. Hudson says, according to Darwin, they live sometimes 

 quite promiscuously together, sometimes they pair. 



PiEASONixG Instincts 



The Bee as an Example of the Im.'portance of acquired and 

 inherited Characters in the Modification of Forms 



I here adduce first a case which in many respects supports 

 ray views in the most striking way, especially with regard to 

 the inheritance of mental cliaracters, and with regard to the 

 great part which is played by correlation in the alteration 

 of the sexual organs. 



We know that in bees the asexual condition of the w^orkers 

 is the result of insufficient nourishment in the larval state, 

 for within the first eight days of their life the larvie which 

 are destined to become workers can by better feeding — by 

 the feeding which the queen -larVcC receive — be reared into 

 sexually-perfect queens, capable of reproduction. 



This is, be it said in passing, one of the most beautiful, 

 incontrovertible instances of the direct influence of external 

 conditions on the development of structure. 



Here also the workers possess a whole series of peculiar 

 characters of the body which are obviously correlated with 



