1894. NEUTER INSECTS AND DARWINISM. 285 



although Lubbock assures us that the exact mode by which the 

 differences are produced is still entirely unknown. 



Into what obvious fallacies Weismann is capable of falling in 

 consequence of his over-zeal for his own views is shown by two cases 

 which I will cite from his first article in the Contemporary. To prove 

 that pammixis alone suffices to bring about the complete disappearance 

 of characters, he adduces the degeneration of the feeding instinct in 

 Polyergus rufescens, which starves to death unless crammed from the 

 crop of a slave-ant. He states correctly that not only the males and 

 females, but the workers also in this species, have altogether forgotten 

 how to recognise their food. He says that this would be an excellent 

 example of the transmission of functional degeneration — " if only these 

 amazons were not sterile." But, of course, the males and females are 

 not sterile, and Weismann is inadvertently aiming weapons at himself. 

 Another curious fallacy in the same article is the reference to the skin 

 armature of hermit-crabs as one of those passive organs which cannot 

 be strengthened by use, and yet which disappear when they cease to 

 be useful. This case seems so convincing to Weismann that he can 

 only suppose that Spencer ignores it because the philosopher is 

 unacquainted by personal observation with facts so familiar to the 

 naturalist. And yet the wonder really is that Weismann should ignore 

 the fact that the rigid cuticle of Crustacea is not merely an armour of 

 defence, but an external skeleton to which the muscles are attached, 

 and which is necessary to their movements. Every naturalist ought 

 to know that in the tail of the hermit-crab the muscles and the cuticle 

 are equally degenerate, have diminished pari passu, except certain 

 appendages forming the apparatus at the end of the tail by which the 

 hermit holds on to the shell he inhabits, and in this apparatus both 

 the muscles and the cuticle are well-developed. In this case the weapon 

 so confidently aimed at the despised philosopher bursts in the natura- 

 list's hands, and does more damage to himself than to his adversary. 

 I have not hither to dealt with the question of habits and instincts. 

 It is confidently held by selectionists like Mr. Piatt Ball that the 

 wonderful instincts of the sterile forms of social insects could never 

 have been present in the ancestral perfect insects, and can only be 

 explained by the natural selection of parents which had the power 

 of producing workers that possessed them. Spencer maintains that 

 the instincts are inherited from ancestral perfect insects, in which they 

 were developed by habit and practice. That this is largely true there 

 can be little doubt, when we consider the numerous intermediate 

 cases between solitary females and the most highly-developed com- 

 munities. What remains, it seems to me, is easily explained as the 

 result of individual education. It is certain that the newly-emerged 

 worker wasp begins making cells and feeding larvae in imitation of 

 her mother, having no sexual instinct and no males to mate with. 

 The worker wasp inherits much directly from her mother, although 

 not sexual instincts, and learns much by imitation. It is true that 



