Most physiologists, resting upon the evidence of analogy, agree in attributing _five senses_ to insects: (+Dr. Virey+, as will be seen further on, ascribes to them _seven senses:_) though there is a difference of opinion as to the organs by which those senses are conveyed. The _antennæ_ for instance, have been regarded by some as the organs of smell, by others as the organs of touch, and by a third class as the organs of hearing. With the substitution of taste forbearing, the same opinions have been maintained respecting the _palpi;_ nor can the question even now be considered as settled. The prevailing opinion seems to be, that the antennæ are explorers or tactors, but that they are also applied to other uses; the effects produced by their excision indicate that they are organs of the highest importance. _Vide_ Senses of Bees. +Messrs. Kirby+ and +Spence+ notice the analogy borne by antennæ to the ears of vertebrate animals, such as their corresponding in number and standing out from the head. No ether organ has been found which can be supposed to represent the ear[L]. And what I have said in another place, of their constituting a sixth sense, has received some countenance from the observations of those naturalists. "I conceive," says Mr. K., "that the antennæ, by a peculiar structure, may collect notices from the atmosphere, receive pulses or vibrations, and communicate them to the sensorium, which, [communications] though not precisely to be called hearing, may answer the same purpose." Lehmann calls the function of the antennæ aëroscepsy. A very remarkable instance of the effect produced upon them by sound, is adduced by the authors just quoted, which one of them has thus related. "A little moth was reposing upon my window; I made a quiet, not loud, but distinct noise: the nearest antenna immediately moved towards me. I repeated the noise at least a dozen times, and it was followed every time by the same motion of that organ; till at length the insect, being alarmed, became agitated and violent in its motions. In this instance, it could not be _touch_; since the antenna was not applied to a surface, but directed towards the quarter from which the sound came, as if to listen." [Footnote L: +Marcel de Serres+ thinks he has discovered an organ of hearing in most insects, but does not state its situation.]