y wingless insects have large antennae, this
evidently is not their only function.

The antennae are also often styled the "feelers;" but with our present
incomplete knowledge of their nature, the former term is preferable, as it
does not attempt to define their use as the word "feelers" does.

Considerable variety of form exists in the clubbed tip of the antennae in
various butterflies, as will be seen by reference to Plate II., where three
of the most distinct forms are shown considerably magnified. Fig. 12 is the
upper part of the antenna of the High-brown Fritillary (_Argynnis Adippe_),
the end suddenly swelling into a distinct knob. Fig. 13 is that of the
Swallow-tail Butterfly (_Papilio Machaon_), the enlargement here being more
gradual; and fig. 14 is that of the Large Skipper Butterfly (_Pamphila
Sylvanus_), distinguished by the curved point that surmounts the club.
These differences in the forms of the antennae are found to be excellent
aids in the classification of butterflies, and I shall therefore have
occasion to refer to them more minutely in describing the insects in
detail.

The stems of these organs are found to be tubular, {31} and at the point of
junction with the head the base is spread out (as shown at fig. 15),
forming what engineers call a "flange," to afford sufficient support for
the long column above.

The _legs_ are the last portions of the butterfly framework that require
especial notice, on account of a peculiar variation they are subject to in
different family groups.

It may be laid down as an axiom, that _all true insects have six legs_, in
one shape or another; and butterflies, being insects, are obedient to the
same universal rule, and duly grow their half-dozen legs; but in certain
tribes the front pair, for no apparent reason, are so short and imperfect
as to be totally useless for walking purposes, though they may possibly be
used as hands for polishing up the proboscis, &c. So the butterfly in this
case _appears_, to a hasty observer, to have only _four_ legs.

This peculiarity is a constant feature in several natural groups of
butterflies, and therefore, in conjunction with other marks, such as the
veining of the wings and the shape of the antennae, its presence or absence
is a most useful mark of distinction, in classifying or searching out the
name and systematic place of a butterfly.

* * * * *

{32}

CHAPTER III.

WHAT BUTTERFLIE