ON THE ORIGIN OF THE FORMS OF GALLS. 37 



larvae, and if the explanation accepted by entomolo- 

 gists in elucidating the origin of the forms and 

 colours of larvae — that these serve to protect them, 

 and have been produced by the agency of natural 

 selection — is a valid one, I do not see ho^v we can 

 reject it as explanatory of the forms, colours, and 

 structures of galls. It is at any rate more in 

 harmony with general laws than the poison theory, 

 even although it had more to support it than has 

 hitherto been adduced. 



