THE 
AMERICAN NATURALIST. 
VoL. xiv. — WAY, 1880. — No. 5. 
THE STRUCTURE AND ACTION OF A RUTTERFLY’S 
TRUNK. 
BY EDWARD BURGESS. 
VERY one knows that butterflies and moths, the insects 
forming the group Lepidoptera, often feed on honey, and that 
for the purpose of obtaining it, they are provided with a long 
trunk, or tongue as it is sometimes called, to reach the nectaries 
of flowers. Sometimes this trunk is very long, in the case of our 
common tomato caterpillar moth, for example, its length is three 
inches, while in some allied moths of tropical regions it is greatly 
longer, and botanists and entomologists have often pointed. out 
the relation existing between the length of various long-tubed 
flowers and of the trunks of some species of moths in the same 
region. 
Thanks to the acuteness of Savigny, entomologists have long 
known that this trunk is not an organ sui generis, but simply the» 
metamorphosed maxil/e, or second pair of jaws of biting insects, 
which have become specialized to form a sucking tube. The man- 
dibles or first pair of jaws, which, while the insect was in the 
caterpillar stage were well developed to bite off pieces of leaves or 
other substances then its food, are, in the perfect butterfly, reduced 
to the merest rudiments (Fig. 1, md), only to be found by carefully 
brushing away the thick covering of scales and hairs. The pair 
of maxillze, on the contrary, grow each into a long, gently-tapering 
organ with a deep groove along its inner surface ; which surface 
being applied to that of the opposite maxilla, and held in this 
position by a sort of dove-tailing lock, there is formed a hollow 
trunk through which liquid food can be drawn into the mouth, 
VOL. XIV.—No. V. 21 
