ARGENTINE COW-BIRD 87 



tageous. Of the Coccyzas melanocoryphus, the only 

 one of our three Coccyzi whose nesting habits I am 

 acquainted with, I can say that it never begins to 

 incubate till the full complement of eggs are laid 

 that its young are hatched simultaneously. But if 

 it is sought to trace the origin of the European 

 Cuckoo's instinct in the nesting-habits of American 

 Coccyzi, it might be attributed not to the aberrant 

 habit of perhaps a single species, but to another and 

 more disadvantageous habit common to the entire 

 genus, viz,, their habit of building exceedingly frail 

 platform-nests from which the eggs and young very 

 frequently fall. By occasionally dropping an egg in 

 the deep, secure nest of some other bird, an advantage 

 would be possessed by the birds hatched in it, and 

 in them the habit would perhaps become hereditary. 

 Be this as it may (and the one guess is perhaps as 

 wide of the truth as the other) there are many genera 

 intermediate between Cuculus and Molothrus in which 

 no trace of a parasitic habit appears ; they belong to 

 different orders, and it seems more probable that 

 the analogous instincts originated independently in 

 the two genera. As regards the origin of the instinct 

 in MolothruSf it will perhaps seem premature to 

 found speculations on the few facts here recorded, 

 and before we are acquainted with the habits of 

 other members of the genus. That a species should 

 totally lose so universal an instinct as the maternal 

 one, and yet avail itself of that affection in other 

 species to propagate itself, seems a great mystery. 

 Nevertheless I cannot refrain from all conjecture 



