Rensselaer Union, Volume 7, Number 52, Rensselaer, Jasper County, 16 September 1875 — How the Fly Eats. [ARTICLE]

How the Fly Eats.

The proboscis or elongated tongue' of the fly is an object equally interesting to the anatomist and to the microecopist. It is capable of being entirely retracted within a cavity in the lower part of the head, and of being protruded at will. It consists of a hollow, fleshy sort of tube, dilated at the end into two lobes, and capable of being flattened out beneath into a sucking disc. This disc is furnished with a pair of horny branches, which open out laterally for the purpose of keeping it expanded, and also contains two tubes with a profusion of lateral branches. These tubes seem incomplete upon their under surface and serrated at the edges. Their office has not yet been determined. My own idea—ana I venture it here with the greatest diffidence—is, that only the elastic coating of the tubes is incomplete, and that by forcing air into them, by means of organs in the thorax, the tenseness and resistance of the disc of the proboscis can be regulated at the will of the insect, as the character of the food might require. In other words, air hqre is made to perform the same office which the blood executes in the erectile tissue of the vertebrate animals. The average diameter of the lateral branches of these tubes, ascertained by careful “measurements, conducted by my friend Dod, is the one-thou-sandth part ot an inch. Through the proboscis the fly imbibes its food, which, of necessity, must be, to a certain extent, liquid. If the article upon which it feeds be dry, as a lump of sugar or a crumb of bread* a species of saliva is forced down through the organ and the dissolved particles are then easily sucked up, On each side of the proboscis is a labial palpus, or feeler, by means of which the insect i» probably enabled to gain a more correct idea of its food and the surroundings than it could otherwise acquire. A little above the insertion of the proboscis, and between the eyes, are the two,, delicate antennae, which are thought by some naturalists to contain apparatus for hearing. If time permitted, it w ould be most interesting to note „the wonderful changes rung upon these three organs—the probosds, the palpi and the antennae—in different species —for, in one shape or another, they are common to a great number of insects.— L. D. Morse , in Pen and Plow.