140 The Naturalist in La Plata, 
flowers.”’ If this be so, it is quite certain that the 
juices fail to satisfy them ; and that, like Dr. Tanner, 
who was ravenously hungry during his forty days’ 
fast, in spite of his frequent sips of water, the 
mosquito still craves for something better than a 
cool vegetarian diet. I cannot help thinking, 
though the idea may seem fanciful, that mosquitoes 
feed on nothing. We know that the ephemere take 
no refreshment in the imago state, the mouth being 
aborted or atrophied in these short-lived creatures ; 
but we also know that they belong to an exceed- 
ingly ancient tribe, and possibly, after the earth 
had ceased to produce their proper nourishment 
there came in their history a long hungry period, 
which did not kill them, but lasted until their 
feeding instincts became obsolete, the mouth lost 
its use, and their life in its perfect state dwindled 
to its present length. 
In any case, how unsatisfactory is the mosquitoes’ 
existence, and what a curious position they occupy 
in nature! Let us suppose that, owing to some 
ereat change in the conditions of the earth, rapacious 
birds were no longer able to capture prey, and that, 
by a corresponding change in their organizations, 
they were able to subsist on the air they breathed, 
with perhaps an occasional green leaf and a sip of 
water, and yet retained the old craving for solid 
food, and the old predatory instincts and powers 
undiminished ; they would be in the position of 
mosquitoes in the imago state. And if then fifty 
or a hundred individuals were to succeed every 
year in capturing something and making one hearty 
meal, these few fortunate diners would bear about 
