LETTEES FEOM ALABAMA. 
67 
Now, as I said, the tongue usually lies straight 
down the middle of the breast, but in some of the 
larger Sphinges this organ is destined to be, in the 
future moth, of unusual length and size ; and there- 
fore, as in this species, it is not folded down with the 
other members, and covered only by the common 
skin of all, but has a separate skin or sheath, 
projecting from the head, with the tip (in some 
instances recurved) resting on the breast, looking 
very much like the trunk of an elephant^ The 
tongue or sucker, when the perfect insect is evolved, 
is an organ well worth a moment’s examination, 
as a beautiful instance of the modification of a part 
to adapt it to altered circumstances. Look here ! 
I will unfold the apparatus, nearly two inches long, 
yet when rolled up in this beautiful spiral, curl 
within curl, scarcely larger than the head of the pin 
with which I am opening it. It is tubular through- 
out its whole length ; and, what is singular, it is 
composed of two parts perfectly separable, you see, 
each part being a cylinder, yet when placed side 
by side, meeting in such a manner as to form a 
tube quite air-tight between the two lateral ones. 
It is this central tube which forms the sucking- 
pump ; the outer ones being intended (so it is 
asserted) for the reception of air. In what way 
suction is performed, however, is still a mystery. 
Now, in this long cylinder, who could detect the 
slightest analogy to the hard, toothed jaws of a 
beetle ? yet, in fact, the two halves of the cylinder 
are neither more nor less than the two jaws, altered 
and modified to suit the necessities of the insect ; 
for a Sphinx placed at the outside of a tubular 
flower, furnished only with a pair of short, hard 
jaws, would be in somewhat the same condition as 
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