Forest Preserve District of Cook County, Illinois
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Lice
Nature Bulletin No, 292-A   February 3, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F, Eisenbeis, Supt. of Conservation

LICE
Humorous songs and poems have been written about the flea but there is nothing funny about a louse. Fortunately, lice are known to the vast majority of cleanly people only by hearsay: as loathsome parasites not to be discussed in polite society, However, all warm-blooded animals are subject to lice and they are a problem on farms, in menageries and circuses, and among wildlife. Human lice, common in pioneer days, are still common in slums, "flop houses", prisons, labor camps, and especially in wartime -- wherever crowded unsanitary living conditions prevail, Body lice or "crumbs" got the name "graybacks" during our civil war; and in the trenches of World War I it was a universal pastime to "read your shirt for cooties", Head Lice were nicknamed "galloping dandruff".

The louse is a small wingless primitive insect, with a flattened body, which passes through three stages as an egg, a nymph and an adult. There is no metamorphosis: the newly hatched nymph, except in size, looks like the adult. The egg or "nit" is glued to a hair or feather of the host and the insect spends its whole life on that animal unless it is removed or transferred to another of the same kind. In general, each species of animal has one or more species of lice peculiar to it. There are two types; the sucking lice and the chewing lice.

There are probably 400 species of sucking lice. This type, found only on mammals, has a fleshy snout which contains mouthparts for piercing the skin and sucking the blood of its host, and this can be greatly extended or withdrawn into its head. The eyes, when they have any, are very imperfect. Each leg has a large claw and a thumblike projection so spaced as to clamp closely around a hair of the particular kind of animal on which that species lives. When the insect crawls awkwardly about, these claws are as annoying as its bites.

The head louse and the body louse, which attack all races of people, have very different habits but are now considered to be varieties of the same species. The former lives on the skin of the head and glues its eggs to the hairs, like a typical louse. The other is unique in that it lives in a person's clothing, lays its eggs in the seams of the clothing, and only goes upon the skin to feed. It is very prolific and dangerous. Aside from the drain upon its host's vitality from loss of blood and constant irritation, with danger of infection from scratching, these lice transmit such diseases as typhus fever, causing epidemics which have killed millions of people. The only other species attacking man is the crab louse. It is not known to transmit any disease and is found only on the white and Negro races.

The bloodsucking lice found on domestic animals have longer snouts. There are three species found on cattle, two on sheep and goats, one on horses, mules and donkeys, one on dogs, and one -- the largest almost one-quarter inch long -- on hogs. Unless drastic control measures are taken, the beast becomes thin and sickly, with scurf and scabs upon its skin where patches of hair have been rubbed off. Its growth and its production of meat, milk, wool or labor are seriously affected. Most wild mammals, including bats, are also subject to lice.

Chewing lice do not suck blood. They nibble on the skin, feathers or hair of the host, run about rather rapidly, and glue their eggs to the feathers or hair. Every kind of domestic fowl, and most wild birds, has one or more species of chewing lice peculiar to it. These have two claws on each leg, whereas most of the chewing lice that attack horses, cattle, deer, sheep, goats, rodents, dogs, cats and other mammals, have only one claw.

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