66 
SEXUAL SELECTION. BIKDS. 
Part It 
an extraordinary noise, the first “ sharp note being not 
“ unlike the crack of a whip.” 66 
d e f 
Fig. 45. Secondary wing-feathers of Pipra deliciosa (from Mr. Sclater, in Proc. Zool. 
1860). The three upper feathers, a, b, c, from the male ; the three lower corresponding 
feathers, d, e,f, from the female. 
a. and d. Fifth secondary wing-feather of male and female, upper surface. b and 
Sixth secondary, upper surface. c and/. Seventh secondary, lower surface. 
The diversity of the sounds, both vocal and instru- 
mental, made by the males of many species during th e 
55 Sclater, in ‘Proc. Zool. Soc.’ 1860, p. 90, and in ‘Ibis,’ vol. i v ’ 
1862, p. 175. Also Salvin, in ‘ Ibis/ 1860, p. 37. 
