60 AFRICAN GAME ANIMALS 



or a slightly different tinge to the coat. Terns which have 

 been dyed indigo or carmine and turned loose are soon 

 accepted by their fellows, and even by their mates, on the 

 old basis. Mr. Spencer Trotter found a male scarlet tan- 

 ager breeding although the hind back and the belly were 

 green; but the startling aberration in color had not con- 

 fused its mate. In one herd of topi we saw an individual 

 with a blazed or white face, like that of its relative, the 

 South African blesbok; but the other topi treated it pre- 

 cisely like one of themselves. Animals with dichromatic 

 color phases, like the red and gray phases of the American 

 screech-owl, and of the cougars we have collected in the 

 Colorado and Arizona mountains, mate together wholly 

 without regard to color. Still more striking are the facts 

 in the case of the white-withered lechwi and the white- 

 eared kob. These animals belong to very closely allied 

 genera and are of about the same size, and they dwell in 

 the same neighborhood along the White Nile— one in the 

 swamps, the other in the dry plains alongside the swamps. 

 Sometimes these herds meet on the edges of the swamps. 

 The females are so alike in shape and color that it needs 

 an inspection close up, including a look at their hoofs, to 

 tell them apart. If animals really needed striking recogni- 

 tion marks to enable the individuals of one sex to recognize 

 the individuals of the other sex of the same species, there 

 could not fail to be numerous hybrids between the kob and 

 lechwi. As a matter of fact, although both species are 

 abundant in the same region, such hybrids never occur, or 

 occur so rarely that they have never been observed. It is 

 evident that the sexes have no difficulty whatever in recog- 

 nizing one another and discriminating against the animals 



