S86 THE ORIGIN OF SPECIES 



been slaughtered, but the breeder has gone with confi- 

 dence to the same stock and has succeeded. Such faith 

 may be placed in the power of selection, that a breed 

 of cattle, always yielding oxen with extraordinarily long 

 horns, could, it is probable, be formed by carefully watch- 

 ing which individual bulls and cows, when matched, pro- 

 duced oxen with the longest horns; and yet no one ox 

 would ever have propagated its kind. Here is a better 

 and real illustration: according to M. Verlot, some varie- 

 ties of the double annual Stock, from having been long 

 and carefully selected to the right degree, always produce 

 a large proportion of seedlings bearing double and quite 

 sterile flowers; but they likewise yield some single and 

 fertile plants. 



These latter, by which alone the variety can be 

 propagated, may be compared with the fertile male 

 and female ants, and the double sterile plants with the 

 neuters of the same community. As with the varieties 

 of the stock, so with social insects, selection has been 

 applied to the family, and not to the individual, for the 

 sake of gaining a serviceable end. Hence we may con- 

 clude that slight modifications of structure or of instinct, 

 correlated with the sterile condition of certain members of 

 the community, have proved advantageous: consequently 

 the fertile males and females have flourished, and trans- 

 mitted to their fertile offspring a tendency to produce 

 sterile members with the same modifications. This proc- 

 ess must have been repeated many times, until that 

 prodigious amount of difference between the fertile and 

 sterile females of the same species has been produced 

 which we see in many social insects. 



But we have not as yet touched on the acme of the 



