150 



HEREDITARY CHARACTERS 



at all. These facts make it perfectly apparent that the in- 

 stincts must be due to inborn variations entirely, and not at 

 all to acquired characters, for the individuals through which 

 they are invariably transmitted do not possess them, and so 

 certainly have made no acquirements in that direction. 1 



Nor are instincts the only characters transmitted through 

 individuals that do not possess them. The same thing 

 happens with regard to very striking physical characters. 

 The soldier ant in the case of true ants is an example. The 

 soldier ants are neuters, and in them the head is greatly 



FlO. 19. A. Male of Typhloponc, formerly classed in a 

 separate genus (Dorylus). B. Female, formerly classed 

 in a separate genus (Dicthadia). C. Neuter soldier 

 (worker). D. Neuter minor (worker). [Actual size.] 



enlarged, as also are the mandibles. Various parts of the 

 body coverings are modified, and serve the purpose of 

 defence. In fact the soldiers of the colony are so different 

 from their parents, the males and queens, that the untrained 

 observer would class them as belonging to a different family. 



1 The bearing of the cases of neuter insects upon the theory of Lamarck was 

 briefly referred to by Darwin in the first edition of the Origin of Species, 1859. 

 Attention was drawn to this suggestion of Darwin's by Professor Poulton in 

 Essays on Evolution, p. 165, where he expressed surprise that after advancing 

 so forcible an argument Darwin had apparently admitted the transmission of 

 acquired characters. These are the only two cases I have been able to find in 

 which this argument has been brought forward. 



