SEXUAL SELECTION 675 



generations; and each stage of paleness would have to be 

 fixed in the males, and rendered latent in the females. 

 The task would be an extremely difficult one, and has 

 never been tried, but might possibly be successfully car- 

 ried out. The chief obstacle would be the early and 

 complete loss of the pale-blue tint, from the necessity of 

 reiterated crosses with the slaty female, the latter not 

 having at first any latent tendency to produce pale-blne 

 offspring. 



On the other band, if one or two males were to vary 

 ever so slightly in paleness, and the variations were from 

 the first limited in their transmission to the male sex, the 

 task of making a new breed of the desired kind would be 

 easy, for such males would simply have to be selected and 

 matched with ordinary females. An analogous case has 

 actually occurred, for there are breeds of the pigeon in 

 Belgium* in which the males alone are marked with black 

 striae. So again Mr. Tegetmeier has recently shown* 

 that dragons not rarely produce silver-colored birds, 

 which are almost always hens; and he himself has bred 

 ten such females. It is, on the other hand, a very un- 

 usual event when a silver male is ^produced; so that 

 nothing would be easier, if desired, than to make a breed 

 of dragons with blue males and silver females. This ten- 

 dency is, indeed, so strong that when Mr. Tegetmeier at last 

 got a silver male and matched him with one of the silver 

 females, he expected to get a breed with both sexes thus col- 

 ored; he was, however, disappointed, for the young male re- 

 verted to the blue color of his grandfather, the young female 

 alone being silver. No doubt, with patience this tendency 

 to reversion in the males, reared from an occasional silver 

 male matched with a silver hen, might be eliminated, and 

 then both sexes would be colored alike; and this very 

 process has been followed with success by Mr. Esqnilant 

 in the case of silver turbits. 



* Dr. Chapuis, "I« Pigeon Voyagenr Beige," 1865, p. 87. 

 » The "Field," Sept. 1872. 



