588 THE ORIGIN OF SPECIES 



characterized. According to this view, we ought occa- 

 sionally to find in the same nest neuter insects, present- 

 ing 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 sur- 

 prisi: gly from each other in size urd sometimes in color; 

 and that tiie extreme forms cp,n 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, while those of in intermediate size are 

 scanty in numbers, Formica flava has larger and smaller 

 workers, with some lOW 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 dissected 

 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 proportion- 

 ally 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 intermediate 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 con- 

 tinually selected which produced more and more of 



