Now, which of our five senses, I would ask—even if developed into extraordinary acuteness in the insect—would account for such an exhibition of clairvoyance as this?
May not, then, this undiscovered sense, whatever may be its nature, reside in the antennæ? for it is a remarkable fact, that the very moths, such as the Eggers, the Emperor, the Kentish Glory, &c., which display the above-mentioned phenomenon most signally, have the antennæ in the males amplified with numerous spreading branches, so as to present an unusually large sensitive surface. This seems to point to some connexion between those organs and the faculty of discovering the presence, and even the condition, of one of their own race, with more, perhaps, than a mile of distance, and the sides of a wooden box, intervening between themselves and their object.
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
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,