Whilst writing this, the current number of the "Entomologist's Weekly Intelligencer" has arrived, and I there read that Dr. Clemmens, an American naturalist, has been lately experimenting on the antennæ of some large American moths, for the purpose of gaining some information as to their function. The article, though very interesting, is too long for quotation here; but it appears that with the moths in question, a deprivation of the whole, or even part of the antennæ, interferes with, or entirely annihilates the power {30} of flight, so that the creature when thus shorn, but not otherwise injured, if thrown into the air seems to have no idea of using his wings properly, but with a purposeless flutter tumbles headlong to the earth. Still this merely goes to prove that the antennæ are the instruments of some important sense, one of whose uses is to guide the creature's flight; but as many wingless insects have large antennæ, this evidently is not their only function. The antennæ 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 antennæ 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 antennæ 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.