In speaking of the antennæ above, as possibly the organs of hearing, I would wish to add, that they evidently possess some complex function, of which, not possessing any analogy, we cannot certainly conceive any notion. They are observed to be used as instruments of touch, and that too of the nicest discrimination. They seem to be extremely sensitive to the vibrations of sound and the undulations of air, and keenly appreciative of atmospheric influences, of heat, of cold, and of electrical agitations. That they are important media in sexual communication must be assumed from their great differences of structure and size in the sexes, probably both as organs of scent and stimulation. I have often observed bees thrust their antennæ into flowers, one at the time, before they have entered the flower themselves, and in some insects, as in the Ichneumons, they are constantly in a state of vibration,—a tribe which, although of the same order, are remote in position from the bees, yet they may be instructively referred to by way of analogy in the discussion of the uses of an organ, whose functions so clearly follow its structure and position in the organization of the entire class of insects, that the analogy might be safely assumed in application to every family of the class, if observation could only correctly ascertain its uses in any one of them. That it is of primary signification to the bees, is sufficiently shown by nature having furnished these insects with an apparatus designed solely to keep the antennæ clean, and which I have described above, when speaking of the structure of the anterior leg. In the social tribes the antennæ are used as means of communication. The social ants, bees, and wasps may be often seen striking each other’s antennæ, and then they will each be observed to go off in directions different from that which they were pursuing. An extraordinary instance of this mode of communication once came under my own notice, having been called to observe it. There was a dead cricket in my kitchen, another issued from its hole, and in its ramblings came across this dead one; after walking round, and examining it with its antennæ and fore legs a short time, it started off. Shortly, either attracted by sound, or meeting it by accident, it came across a fellow; they plied their antennæ together, and the result was that both returned to their dead companion, and dragged him away to their burrowing-place,—an extraordinary instance of intercommunication which I can vouch for.