Antennae, horn-like members on the head of insects and crustaceous animals. The an-tennae are commonly called feelers, but their functions are not understood. In insects they are two in number; in crabs and lobsters there are more than two. The antenna) of insects are usually composed of minute articulated rings, containing nervous threads, muscles, trachea), and cellular tissue, forming organs of sensation, motion, and respiration. In most orders the articulations amount to 10 or 11 in number, although they are much fewer in some species, while in others they reach even to 150. The length of the antennae does not depend on the number of articulations, as they are often long when of only three or four pieces, and the reverse. They are inserted on the front of the head in the region of the eye, and connected by means of a ball and socket. The distinction of sex in some species is marked by the peculiar formation of the antenna). In moths the antenna) of the male are of more simple construction than those of the female. In moths and beetles they are much longer than the body, while in the common house fly they are comparatively short.

Linnaeus and Bergman supposed them to be organs of touch, and they were thence termed feelers; but M. Straus-Durckheim is of the opinion that the antenna) are the insect's organs of hearing. Professor Bonsdorf, of Abo in Finland, and other naturalists, have adopted the same opinion. The younger Huber attributed to ants the use of the antenna) in a sort of language, which he terms the "antennal language," understood not only among ants themselves, but also among the aphides, which furnish the honey-dew on which ants feed.