204 
COLOURS AND COLORATION IN ANIMALS. SEPT., 1892. 
since one would suppose the device as useful among the higher 
as the lower animals. 
In the author’s opinion, some cases of mimicry are so 
striking that they can be explained only on the generally 
received theory, with the proviso that the initial resemblance, 
which must have been considerable, must be set down to 
other causes, such as the influence of like external conditions; 
but other instances of mimicry, which are to be appreciated 
only by insects, must in our present knowledge of insect- 
vision be removed from the category. In the following words 
he sums up his opinions on the matter:—-“Seeing, then, 
that resemblances may occur between animals which either 
cannot be, or are probably not, advantageous to either, it is 
at least necessary to wait for more convincing proofs before it 
can be more than provisionally assumed that natural selection 
is responsible for these resemblances in other cases where 
they appear to us to be useful.” 
We come now to the last section of the work, that which 
deals with Sexual Coloration ; and here the most novel part 
is the account of Mr. Stolzmann’s views, which are as 
follows :—It appears from various observations that among 
birds the males are more numerous than the females. Now 
this preponderance is not advantageous to the species, for the 
bachelor males are not only useless, since they are unmated, 
but they also persecute with their attentions the mated 
females while sitting on their eggs, and at the same time 
lessen the food supplies. Now natural selection is concerned 
not so much with the well-being of the individual as with 
that of the race, and, consequently, anything tending to 
lessen the undue proportion of the less useful sex, and so 
advantage the race, will be seized on by that potent agent in 
evolution. Hence the gaudy colours, crests, spurs, and 
pugnacious habits of the males : the gaudy colours attract 
the notice of enemies, while the plumes impede flight, 
causing their owners to fall an easier prey ; the pugnacious 
habits cause fighting among the males with their spurs, 
which often ends in fatal results. Thus the numbers of the 
males are reduced, and the evil results indicated above are 
minimised. Also, according to Mr. Stolzmann, the love- 
dances and songs of birds are a distraction to protect the 
female from the too constant attentions of the males. 
This is certainly a startling explanation. Mr. Beddard 
thinks it impossible to believe either in it or any other theory 
which ignores the deep-seated differences between the sexes, 
and he insists on the well-known fact that the secondary sexual 
characters of animals are dependent upon the germ glands 
themselves. This is shown, among other instances, by a 
