RECAPITULATION. 459 



drones being produced in such great numbers for one single 

 act, and being then slaughtered by their sterile sisters ; at 

 the astonishing waste of pollen by our fir-trees : at the 

 instinctive hatred of the queen bee for her own fertile 

 daughters ; at ichneumonidse feeding within the living bodies 

 of caterpillars ; or at other such cases. The wonder, indeed, 

 is, on the theory of natural selection, that more cases of the 

 want of absolute perfection have not been detected. 



The complex and little known laws governing the produc- 

 tion of varieties are the same, as far as we can judge, with 

 the laws which have governed the production of distinct 

 species. In both cases physical conditions seem to have 

 produced some direct and definite effect, but how much we 

 cannot say. Thus, when varieties enter any new station, 

 they occasionally assume some of the characters proper to 

 the species of that station. With both varieties and 

 species, use and disuse seem to have produced a considerable 

 effect; for it is impossible to resist this conclusion when 

 we look, for instance, at the logger-headed duck, which has 

 wings incapable of flight, in nearly the same condition as 

 in the domestic duck ; or when we look at the borrowing 

 tucu-tucu, which is occasionally blind, and then at certain 

 moles, which are habitually blind and have their eyes cov- 

 ered with skin ; or when we look at the blind animals in- 

 habiting the dark caves of America and Europe. With 

 varieties and species, correlated variation seems to have 

 played an important part, so that when one part has been 

 modified other parts have been necessarily modified. With 

 both varieties and species, reversions to long-lost characters 

 occasionally occur. How inexplicable on the theory of 

 creation is the occasional appearance of stripes on the 

 shoulders and legs of the several species of the horse-genus 

 and of their hybrids ! How simply is this fact explained 

 if we believe that these species are all descended from a 

 striped progenitor, in the same manner as the several 

 domestic breeds of the pigeon are descended from the blue 

 and barred rock-pigeon ! 



On the ordinary view of each species having been inde- 

 pendently created, why should specific characters, or those 

 by which the species of the same genus differ from each 

 other, be more variable than generic characters in which 

 they all agree ? Why, for instance, should the color of a 

 flower be more likely to vary in any one species of a genus, 

 •if the other species possess differently colored flowers, than 



