208 THE PRINCIPLES OF [Part II. 



On the other hand, he is certain that with the common linnet, the 

 females preponderate greatly, hut unequally during different years; 

 during some years he has found the females to the males as four 

 to one. It should, however, be borne in mind, that the chief sea- 

 son for catching birds does not begin till September, so that with 

 some species partial migrations may have begun, and the flocks 

 at this period often consist of hens alone. .Mr. Salvin paid par- 

 ticular attention to the sexes of the humming-birds in Central 

 America, and he is convinced that with most of the species the 

 males are in excess ; thus, one year he procured 204 specimens 

 belonging to ten species, and these consisted of 166 males and of 

 38 females. With two other species the females were in excess : 

 but the proportions apparently vary either during different sea- 

 sons or in different localities ; for on one occasion the males of 

 Campylopterus hemileucurus were to the females as five to two, 

 and on another occasion 48 in exactly the reversed ratio. As bear- 

 ing on this latter point, I may add that Mr. Powys found in Corfu 

 and Epirus the sexes of the chaffinch keeping apart, and " the fe- 

 males by far the most numerous; " while in Palestine Mr. Tris- 

 tram found " the male flocks appearing greatly to exceed the fe- 

 male in number." 49 So again with the Quiscalus major, Mr. G-. 

 Taylor 60 says that in Florida there were " very few females in 

 proportion to the males," while in Honduras the proportion was 

 the other way, the species there having the character of a po- 

 lygamic. 



FISH. 



With fish the proportional numbers of the sexes can be ascer- 

 tained only by catching them in the adult or nearly adult state ; 

 and there are many difficulties in arriving at any just conclusion. 51 

 Infertile females might readily be mistaken for males, as Dr. Gun- 

 ther has remarked to me in regard to trout. With some species 



48 ' Ibis,' vol. ii. p. 260, as quoted in Gould's ' Trochilidse,' 1861, p. 52. 

 For the foregoing proportions, I am indebted to Mr. Salvin for a table of 

 his results. 



49 'Ibis,' 1860, p. 137; and 1867, p. 369 

 60 'Ibis,' 1862, p. 137. 



61 Leuckart quotes Bloch (Wagner, ' Handworterbuch der PLys.' B. 

 TV. 1853, s. 775), that with fish there are twice as many males as females. 



