30 0 hscrzuUioiis on So))i(' Hybrids of the I'locridac. 
are rarely fertile ; they are often great teases and hinder their 
companions (the mated pairs) from reproducing their species. 
Indeed my personal taste inclines me rather to study the manners 
of my proteges, and some peculiarity caught in the living 
creature pleases me more than the display of some strange and 
borrowed magnificence. Hybridization, from this point of view, 
has an advantage of its own, even if the hybrids are less inter- 
esting'; it allows us to observe, during" the mating season, the 
habits of rare " animals " which it has been impossible to mate 
with one of their own species. In these curious unions, the 
instinct of each parent is almost completely preserved. ' This 
is shown in the case of hybridization, quoted by Russ, between a 
White-headed Munia and a Japanese Sparrow; neither father 
nor mother modified in the slightest the kind of food which each 
species gives to its young during' the rearing period. That is 
the general rule. We may then infer that in all probability the 
birds observed would act in the same way if they 'were mated 
with a male or female of their own species. Sometimes, how- 
ever, it is not so, and it has been established, for example, that 
most of the Fringillidcs mated with a female canary do not 
feed their young, while even in captivity they share this task with 
their mate. 
But the hybridization allows of observations of another 
kind, and it is very wrong for certain people to regard it as a 
pastime with no import. Does not the study of hybrids, 
whether they be born in captivity or in freedom, permit the 
classifier to draw some useful conclusions on the affinity of 
species? And does not the comparison of the parents with 
their young, especially when the latter are fertile, give the 
biologist an opportunity to make fruitful observations? Is it 
necessary to recall here how much light experiments in hybrid- 
ization have, of late years, thrown in the obscure matter of 
transmission of ancestral traits? 
It was not considerations of this kind, one will no doubt 
believe, which gave me the idea of uniting one of my 
Grenadines* (Granatina graxatina. L.) with a female Cordon 
Bleu. I had remarked on the great affinity between these two 
species, and in 1916, despairing of finding females to mate with 
* Violet-eared VVaxbill.— Eo., B.N, 
