Butterflies and Moths are supposed to be directed by this sense to the discovery of their mates. If the female of the eggar moth (Phalæna quercus) be inclosed in a box, and placed in the neighbourhood of the males, they are attracted to the spot in such numbers as to show clearly that they are sensible of her presence. We have analogous instances of the existence of this faculty in other insects. The flesh-fly (Musca vomitoria) occasionally deposits its eggs on plants of the Stapelia genus, no doubt from their odour resembling that of putrefying flesh. This may be regarded by some as an evidence of mistaken instinct; but from what I have said in the chapter on Instinct, I think that my readers will consider this to be erroneous, and that it should rather be regarded as affording presumptive evidence of mistaken judgement. Instinct would direct the creature to deposit its eggs where the larvæ when hatched would be furnished with the means of subsistence, instead of thus exposing them to perish. At all events it affords tolerably good evidence of the existence of an organ of smell in the insect.
The sense of Touch in bees, that is their active or exploring touch, seems to be very acute. To the nicety of this sense has been attributed their power of commencing and carrying on their works amid the darkness of the hives. The recognition of their queen evinces the existence of some such sense; for the experiments related at [page 292], indicate that her presence is not ascertained either by the organs of sight, hearing, or smell.
The Antennæ have generally been considered as their organs of touch; and indeed, in popular language, they are usually called Feelers or horns; they have likewise assigned to them the office of wiping and cleaning the eyes. The antennæ, however, are not regarded as feelers by our leading entomologists: at present their uses are not clearly defined. Some have regarded them as organs of smell; others as organs of hearing; a third party have conceived that they perform some function of which man has no definite idea,—supplying the insect with a sixth sense, an intermediate faculty, according to Messrs. Kirby and Spence, between hearing and touch, rendering it sensible of the slightest movement of the circumambient air. Dr. Evans designates the antennæ as their sight-supplying sense;
“The same keen horns, within the dark abode.
Trace, for the sightless throng, a ready road,
While all the mazy threads of touch convey,
Shot inward to the mind, a semblant day.”
Evans.
The antennæ, of which there are only a single pair, proceed from the anterior part of the head before the eyes.
The Palpi are generally considered as the true feelers; which, as well from their texture as from the manner in which insects apply them to their food before they begin to eat it, seems probable: Cuvier and Lehmann were of this opinion. The palpi are attached to the under jaws and lips, and are four in number. In some respects they bear analogy to the antennæ; but the latter, being more articulated, have an extended power of motion. Some insects with small antennæ are observed to have very large palpi, which gives reason to suppose, that although their offices may be different, they are intended to assist each other.
The antennæ appear to be the more important organs of the two; as the palpi, when removed, have not been found to occasion much apparent inconvenience; whilst from the experiments of Huber and others, it appears that the excision of the antenna deprives the insect of the perfect exercise of its functions. It seems immediately to lose its instincts. The amputation of one antenna produces no effect; but if both be cut off near the root, the bee no longer possesses the power of guiding itself; it cannot direct its tongue to receive food from its companions, nor take any share in the operations of the family; but exhibits perfect indifference, and keeps near the entrance, apparently for the sake of light; when that is withdrawn, it soon leaves the hive to return no more. “Their departure,” says Huber, “must be ascribed to the loss of that sense, which is employed to guide them in the dark.”
That bees possess a fine sense of Taste, may be readily conceived from the delicious food which they collect, and from their having a preference for those flowers that afford the best honey, whenever such flowers grow abundantly in the neighbourhood of the hives. Hence the superiority of the honey of Narbonne, Hymettus, and Pontus. Huber regards Taste as the least perfect of the senses of bees, but the reasons he gives for this opinion are unsatisfactory. Indeed the tongue of the bee is an organ so considerably developed, as to afford very strong evidence of its power of discrimination in the selection of food. Cuvier considers it to be one of the primary functions of its organization.