232 OBJECTIONS TO NATURAL SELECTION. [Chap. VIII. 



mediate 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 arid 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 of Myrmica. For 

 the workers of Myrmica have not even rudiments of ocelli, though 

 the male and female ants of this genus have well-developed ocelli. 



I may give one other case : so confidently did I expect occasion- 

 ally to find gradations of important structures between the different 

 castes of neuters in the same species, that I gladly availed myself 

 of Mr. F. Smith's offer of numerous specimens from the same 

 nest of the driver aut (Anomma) of West Africa. The reader will 

 perhaps best appreciate the amount of difference in these workers, 

 by my giving not the actual measurements, but a strictly accurate 

 illustration : the difference was the same as if we were to see a set 

 cf workmen building a house, of whom many were five feet four 

 inches high, and many sixteen feet high ; but we must in addition 

 suppose that the larger workmen had heads four instead of three 

 times as big as those of the smaller men, and jaws nearly five 

 times as big. The jaws, moreover, of the working ants of the 

 several sizes differed wonderfully in shape, and in the form and 

 number of the teeth. But the important fact for us is, that, 

 though the workers can be grouped into castes of different sizes, 

 yet they graduate insensibly into each other, as does the widely- 

 different structure of their jaws. I speak confidently on this 

 latter point, as Sir J. Lubbock made drawings for me, with the 

 camera lucida, of the jaws which I dissected from the workers of 

 the several sizes. Mr. Bates, in his interesting ' Naturalist on the 

 Amazons,' has described analogous cases. 



With these facts before me, I believe that natural selection, by 

 acting on the fertile ants or parents, could form a species which 

 should regularly produce neuters, all of large size with one form 

 of jaw, or all of small size with widely different jaws ; or lastly, 

 and this is the greatest difficulty, one set of workers of one size 

 and structure, and simultaneously another set of workers of a dif- 

 ferent size and structure ; — a graduated series having first been 

 formed, as in the case of the driver ant, and then the extreme 

 forms having been produced in greater and greater numbers, through 

 the survival of the parents which generated them, until none with 

 an intermediate structure were produced. 



An analogous explanation has been given by Mr. Wallace, of 

 the equally complex case, of certain Malayan Butterflies regularly 



