110 
EOTAL HOETICTJLTUEAL SOCIETY. 
Selection. That operation is going on equally upon all, and 
under that hypothesis mimicry is just as powerful an influence in 
modifying and producing forms as any other ; and there is no 
reason whatever why it should have less conspicuous results ; 
indeed it should have more, if we judge by the long-continued 
persistence of influence which must have been in operation to 
produce such exact resemblances, and which, indeed, seems very 
much thrown away when confined to the 1 in 1000 mentioned 
by Mr. Bates. 
Although mimicry occurs between various tribes or genera, it 
has been observed most frequently in connexion with the most 
common species of the country. This is what would naturally 
be the case with hybridization, supposing all to start fair and to 
be equally liable to hybridization. But this is an assumption 
which we are scarcely warranted in making, and I therefore do 
not press this inference further than as of some conditional 
value. 
After the second generation of hybrids in plants, it was first 
shown by M. JN'audin, and is now well known to all hybridizers, 
that those which do not revert to type break out into an overflow 
of irregular variation, which supplies many of his most remarkable 
sports to the horticulturist, and many of his most puzzling diffi- 
culties to the systematic botanist. On the assumption that the 
mimicry in question is the result of hybridization, we should 
therefore expect to find a marked degree of variation among the 
mimicking species. And so we do. Mr. Bates figures no less 
than fifteen varieties of Leptalis IthomicE, one of his mimics, 
which itself mimics seven different species (all very close to each 
other, however, and perhaps scarcely deserving the name of 
independent instances). Mr. Trimen figures six varieties of 
Fapilio 31erope, which supplies four of his instances of mimicry ; 
and Mr. Wallace's imitating Papilios were in like manner re- 
markable for their variations. It seems a fair inference that 
when the mimicking species are not variable they have been 
established before the second generation of hybrids, and where 
they are variable they have been established subsequent to the 
second generation, and have experienced the usual shock to 
stability occasioned by such repeated loosening of the fetters of 
specific identity. 
Mr. Bates's list of mimics and mimicked species shows, too, 
that when a species is mimicked by one species or genus it is 
