216 OBJECTIONS TO THE THEOKY [CHAP. VIII. 



workers of another caste, and they have an enormously developed 

 abdomen which secretes a sort of honey, supplying the place of 

 that excreted by the aphides, or the domestic cattle as they may 

 be called, which our European ants guard and imprison. 



It will indeed be thought that I have an overweening confidence 

 in the principle of natural selection, when I do not admit that 

 such wonderful and well-established facts at once annihilate the 

 theory. In the simpler case of neuter insects all of one caste, 

 which, as I believe, have been rendered different from the fertile 

 males and females through natural selection, we may conclude 

 from the analogy of ordinary variations, that the successive, 

 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 advantageous modification, all the 

 neuters ultimately came to be thus characterised. According to 

 this view we ought occasionally to find in the same nest neuter 

 insects, 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 some- 

 times 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 rudimentary. Having carefully dis- 

 sected several specimens of these workers, I can affirm that the 

 eyes are far more rudimentary in the smaller workers than can be 

 accounted for merely by their proportionally lesser size; and I 

 fully believe, though I dare not assert so positively, that the 

 workers of intermediate size have their ocelli in an exactly inter- 

 mediate condition. So that here we have two bodies of sterile 

 workers in the same nest, differing not only in size, but in their 

 organs of vision, yet connected by some few members in an 

 intermediate condition. I may digress by adding, that if the 

 smaller workers had been the most useful to the community, and 

 those males and females had been continually selected, which 

 produced more and more of the smaller workers, until all the 

 workers were in this condition; we should then have had a 

 species of ant with neuters in nearly the same condition as those 



