360 OBJECTIONS TO THE THEORY [Chap. VIII. 



from the analogy of ordinary variations, that the succes- 

 sive, slight, profitable modifications did not first arise 

 in all the neuters in the same nest, but in some few 

 alone; and that by the survival of the communities with 

 females which produced most neuters having the ad- 

 vantageous modification, all the neuters ultimately came 

 to be thus characterised. According to this view we 

 ought occasionally to find in the same nest neuter in- 

 sects, presenting gradations of structure; and this we 

 do find, even not rarely, considering how few neuter 

 insects out of Europe have been carefully examined. 

 Mr. F. Smith has shown that the neuters of several 

 British ants differ surprisingly from each other in size 

 and sometimes in colour; and that the extreme forms 

 can be linked together by individuals taken out of the 

 same nest: I have myself compared perfect gradations of 

 this kind. It sometimes happens that the larger or the 

 smaller sized workers are the most numerous; or that 

 both large and small are numerous, whilst those of 

 an intermediate size are scanty in numbers. Formica 

 flava has larger and smaller workers, with some few 

 of intermediate size; and, in this species, as Mr. F. 

 Smith has observed, the larger workers have simple eyes 

 (ocelli), which though small can be plainly distinguished, 

 whereas the smaller workers have their ocelli rudimen- 

 tary. Having carefully dissected several specimens of 

 these workers, I can affirm that the eyes are far more 

 rudimentary in the smaller workers than can be ac- 

 counted for merely by their proportionally lesser size; 

 and I fully believe, though I dare not assert so posi- 

 tively, that the workers of intermediate size have their 

 ocelli in an exactly intermediate condition. So that 

 here we have two bodies of sterile workers in the same 



