HYBRIDS AND DEGENERACY. 155 
to the entomologist, but what I wish to consider is whether 
they have any power of reproduction, at least in a state of 
captivity. 
In the South of France we have a very local species of 
Papilio; P. Alexanor, which, although of the same shape and 
colour as P. Machaon, has its upper wings very similar to those 
of P. Podalirius. Might not Alexanor, although a distinct and 
well-established species, have been originally the product of a 
natural crossing of AMachaon with Podalirius? If crossings 
take place in a state of captivity, they may also take place in a 
state of liberty, and produce those species which we find so 
closely allied. 
Yet what I am going to say respecting the hybrids of 
A. Yama-Mai and A. Pernyi would go against this possibility of 
new species being permanently obtained by natural crossings, 
but it is well known that in a state of confinement, Lepidoptera 
bred from the same small stock, degenerate to such an extent 
that about the third season the ova obtained become infertile, or 
the young larve too weak to live. It has been the case with 
several species I have bred, and I should like to hear that this 
was only accidental, and that the same species could be bred in 
confinement on a small scale for a long succession of years 
without showing any signs of degeneracy. With hybrids, 
degeneracy in a state of captivity would of course be much 
greater than with natural and well-established species. 
From the fact that Lepidoptera, bred from the same small 
stock in a state of confinement, degenerate and usually become 
extinct in the third year, it must not be concluded that 
consanguinity is the cause of it. Want of space, of pure air, and 
proper food, may probably be the causes. In support of this I 
may mention that M. V. La Perre de Roo has contributed to the 
‘Bulletin de la Société d’Acclimatation,’ several papers of the 
highest interest and importance on “ The pretended fatal effects 
of consanguineous alliances,” in which the author, after twenty 
years’ experience with various species of animals, says that 
consanguinity is not a cause of degeneracy; that whenever the 
latter takes place it is due to other causes which have not been 
discovered. 
M. La Perre de Roo maintains that degeneracy through 
consanguinity in the human race, as well as in all other animals, 
