The Evidence from Sexual Characters. 201 



The African hornbill inflates the scarlet bladder-like wat- 

 tle on its neck, and with its wing drooping and tail ex- 

 panded makes qnite a grand appearance. Even the iris of 

 the eye is sometimes more brightly colored in the male 

 than in the female, and this is frequently the case with the 

 beak, for instance in our common blackbirds. In Buceros 

 corrugatus, the whole beak and immense casque are col- 

 ored more conspicuously in the male than in the female, 

 and the oblique grooves upon the sides of the lower 

 mandible are peculiar to the male sex. The males are 

 often ornamented with elongated feathers or plumes, 

 springing from almost every part of the body. The 

 feathers on the throat and breast are sometimes devel- 

 oped into beautiful ruffs and collars. The tail feathers 

 are frequently increased in length, as we see in the tail 

 of the Argus pheasant The body of this latter bird is 

 not larger than that of a fowl, yet the length from the 

 end of the beak to the extremity of the tail is no less than 

 five feet three inches. . . . Nor need much be said 

 on the wonderful differences of color between the sexes, 

 or on the extreme beauty of the males of many birds. 

 The common peacock offers a striking instance. Fe- 

 male birds of Paradise are obscurely colored and desti- 

 tute of all ornaments, while the males are probably, the 

 most highly decorated of all birds, and in so many ways 

 that they must be seen to be appreciated. The elongated 

 and golden orange plumes which spring from beneath the 

 wings of the Paradisea aiwda, when vertically erected 

 and made to vibrate, are described as forming a sort of 

 halo, in the centre of which the head looks like a little 

 emerald sun, with its rays formed by the two plumes. 

 In another most beautiful species the head is bald and of 

 a rich cobalt blue crossed by several lines of black vel- 

 vety feathers. Male humming birds almost vie with birds 



