Mosquitoes and Parasite Problems. 141 
the same proportion to all the raptors on the globe 
as the mosquitoes that succeed in sucking blood to 
their unsuccessful fellows. In the case of the hawks, 
the effect of the few meals on the entire rapacious 
family or order would certainly be nil; and it is 
impossible to believe for a moment that the com- 
paratively infinitesimal amount of blood sucked by 
mosquitoes can serve to invigorate the species. 
The wonder is that the machinery, which accom- 
plishes nothing, should continue in such perfect 
working order. 
When we consider the insect’s delicate organ, so 
admirably fitted for the purpose to which it is ap- 
plied, it becomes difficult to believe that it could 
have been so perfected except in a condition of 
things utterly unlike the present. There must have 
been a time when mosquitoes found their proper 
nourishment, and when warm mammalian blood 
was as necessary to their existence as honey is to 
that of the bee, or insect food to the dragon-fly. 
This applies to many blood-sucking insects besides 
mosquitoes, and with special force to the tick tribes 
(Ixodes), which swarm throughout Central and South 
America; for in these degraded spiders the whole 
body has been manifestly modified to fit it for a 
parasitical life ; while the habits of the insect during 
its blind, helpless, waiting existence on trees, and 
its sudden great development when it succeeds in 
attaching itself to an animal body, also point irre- 
sistibly to the same conclusion. In the sunny up- 
lands they act (writes Captain Burton) like the 
mosquitoes of the hot, humid Beiramar. “The 
nuisance is general ; it seems to be in the air; every 
