Antennae
Aiton's Encyclopedia (1910)
a pair of feeling organs peculiar to insects, crayfish, and closely related animals. They are usually threadlike or club-shaped, and are inserted between, or in front of, the eyes by a ball and socket joint. They are moved by small muscles at the base within the head. The antennae of some insects are simple; others are branched; some are straight; some curved. Insects use their antennae for many purposes. A nerve from the brain extends through the antenna to its tip, making this organ as sensitive as the eye, ear, or the tongue of ordinary animals. Ants seem to communicate with each other by rubbing their antennae together. The honey bee works in the dark, making its cells of exactly the right size and shape, its only guide being measurements made by the antennae, just as a sculptor molds his model with the aid of his finger tips. It is now well understood that many insects not only feel, but hear and smell, and are sensitive to light by means of these wonderful organs. If a bee loses a leg or a wing, it doesn't seem particularly distressed; but when its antennae are cut off, it is dazed and stupefied as though a part of its brain had been removed. It has been found that if an eye of a crayfish is cut off from its stalk, an antenna frequently develops in its place. If an antenna is removed from the head of a crayfish, an antenna, not an eye, regenerates in place of the old one. See Insects
What Has Changed in the Last Century
Aiton's in 1910 had the essentials right — antennae are jointed, muscled, richly innervated organs that feel, smell and in some cases hear — but the mechanism was a blank. Since then the antenna has been shown to be an insect's chief chemical sense organ, packed with sensilla whose receptor neurons were finally pinned to specific odour-receptor genes in the fruit fly in 1999; hearing, where it exists in the antenna, is done by Johnston's organ at the base, as in mosquitoes and Drosophila. The idea that ants "communicate with each other by rubbing their antennae together" has been recast: the antennae are reading chemical signatures, above all the trail and alarm pheromones and cuticular hydrocarbons worked out from the 1950s onward. Two other corrections: antennae are not "peculiar to insects, crayfish" and kin but are shared with millipedes and centipedes, and the odd regeneration experiments cited here found a modern echo in the fruit-fly Antennapedia mutation, in which a leg grows where an antenna should be.
Written for this edition, 2026.