Chap. XV.] LENGTH OF TAIL IN FEMALE. 157 



the male, and its consequent diminution or complete sup- 

 pression through natural selection. But 1 will take a 

 more favoi'able case, namely, the length of the tail. The 

 long train of the peacock would have been not only incon- 

 venient but dangerous to the peahen during the period of 

 incubation and while accompanying her young. Hence 

 there is not the least a priori improbability in the develop- 

 ment of her tail having been checked through natural 

 selection. But the females of various pheasants, which 

 apparently are exposed on their open nests to as much 

 danger as the peahen, have tails of considerable length. 

 The females as well as the males of the Menura superba 

 have long tails, and they build a domed nest which is a 

 great anomaly in so large a bird. Naturalists have won- 

 dered how the female Menura could manage her tail during 

 incubation ; but it is now known ' that she " enters the nest 

 head first, and then turns round with her tail sometimes 

 over her back, but more often bent round by her side. 

 Thus in time the tail becomes quite askew, and is a toler- 

 able guide to the length of time the bird has been sit- 

 ting." Both sexes of an Australian kingfisher ( Tanysiptera 

 Sylvia) have the middle tail-feathers greatly lengthened; 

 and, as the female makes her nest in a hole, these feathers 

 become, as I am informed by Mr. R. B. Sharpe, much 

 crumpled dui'ing nidification. 



In these two cases the great length of the tail-feathers 

 must be in some degree inconvenient to the female ; and, 

 as in both species the tail-feathers of the female are some- 

 what shorter than those of the male, it might be argued 

 that their full development had been prevented through 

 natural selection. Judging from these cases, if, with the 

 peahen, the development of the tail had been checked only 

 when it became inconveniently or dangerously long, she 

 would have acquired a much longer tail than she actually 



^ Mr. Ramsay, in Proc. Zoolog. Soc' 1868, p. 50. 



