PEDICULVS, in natural history, the/mac, a genus of insects, of the order Aptera. Generic character : mouth with a retrac tile, recurved sucker, without proboscis ; no thelers ; antenna as long as the thorax; two eyes ; abdomen depressed ; legs six, formed for running. These live by ex tracting animal the larva; and pu pa are six-footed, and nimble, resem bling the perfect insect. There are be tween seventy and eighty species ; of these some infest the bodies of quadru peds, others of birds, and some even of in sects themselves. P. humanus, or com mon louse, is distinguished by its pale, livid colour, and lobated, oval abdomen. It is produced from a small oval egg, Po pularly called by the name of a nit, which is fastened or agglutinated by its smaller end to the hair on which it is deposited : from this egg proceeds the insect, com plete in all its parts, and only different from the parent animal in its smaller size. When examined by the microscope, it is seen that the trunk, or proboscis, which is generally concealed in its sheath or tube, is of a very sharp form, and is fur nished towards the upper part with a few reversed aculei or prickles ; the eyes are large, smooth, and black ; the stomach and intestines afford a very distinct view of the peristaltic motion ; the legs are each terminated by a double claw, not very much unlike that of a lobster, but of a sharp er form ; and the whole animal is every where covered by a strong granulated skin. Few insects are more prolific than
the louse. It is said, that in about eight weeks a louse might see five thousand of its own descendants.
Each species of animal has a species of louse peculiar to itself; and sometimes more than one species, but the same is not to be found on two distinct animals. It is a fact well worthy of remark, that the louse of the negro is specifically dis tinct from that of the white marl