This unwelcome immigrant may be recognised by its grooved and tubercled back, which ranges from white to black, through yellow and brown. Its plentiful slime is white and viscid. It eats earthworms and insects beside its regular diet. This species is about i inches long. It is native to Europe, but naturalised in this country.
These are the slugs sold in British towns on the prescription of physicians, and thoroughly believed in by the country folk as "good for consumption." They are swallowed alive, or first boiled in milk.
Pliny recommends "a plaister made of slugs with their heads cut off" to be bound on the forehead as a cure for headache. He thought slugs were young snails not yet old enough to have secreted shells.
Genus ARION, Fer.
Shell wanting, or resolved into several granules; body slug like, narrow, furrowed; mantle small, free in front and on sides, orifice of lung sac near fore part, slime gland in the tail, secre tion viscid, transparent.
A small genus native to the eastern hemisphere, but with representatives naturalised in this country.
The Large Black Slug (A. ater, Linn.) has no friendship with gardeners, but a standing feud. By day and by night the creature eats, exhibiting a voracity that is rarely equalled. Our quarrel is based upon the fruit it steals, but its diet is remarkably varied. In captivity a specimen consumed the following items: five other slugs, a dead mussel, some insects, and a little toilet soap. It accepted also various garden vegetables, dead mice, birds, earthworms, bread, wild plants, including several mushrooms, some poisonous, leaves of polypody fern, sea holly and butter cup. After a two-days' fast one scraped the news off a portion of the daily paper. Another fed eagerly on a handful of beach sand. Slugs can go hungry for days at a time, but they must have water, or they die.
A full grown slug will reach five inches in length. The body is covered with a shingling of papillae, but no furrows. In colour 284 The Land Slugs it is white, yellow, brown or black, according to the food plants and the moss and leaves among which its life is spent.
The Arions are late in going into hibernation, sustaining a much greater degree of cold than the shell-bearers. The eggs
are laid at intervals covering several weeks, an individual pro ducing several hundred. They hatch in forty to sixty days. The young slug buries itself in the ground for four or five days, and emerges nearly twice its original size. The adult slug, after laying its eggs, frequently dies from sheer exhaustion. The weight of the eggs laid often exceeds three-fourth of the slug's own weight.
In every batch of slug's eggs many are devoured by the larvae of a small fly which lays its eggs inside after puncturing the thin shell. Centipedes, ants and other insects devour the young. So do other slugs, and birds have a great liking for them.
A favourite pastime with A. ater is to take a bath. It often remains under water for hours. One specimen, submerged and held under for three days, did not perish, but recovered in short order. Small parasites make life miserable for many a healthy slug. They may be seen swimming in a beaker into which a slug is put for a bath. Perhaps bathing is the practical means of getting rid of these pests.
A slug will often eat the slime and even the skin off the back of another. Though this is certain death to the victim, he stands still, making no objection, and seeming quite indifferent to the business which gives his companion so much pleasure.
Genus ARIOLIMAX, MOrch.
Mantle with free edges all around, and contains a stiff plate of limy composition; body slug-like, blunt.
The Great Yellow Slug (A. Columbianus, Gld.) frequents damp, shady places throughout the year on the Pacific coast, and spends the rainy months in the fields. It is 'attracted by such a bait as a bit of orange peel or a dish of milk. The many toothed radula and cross-ribbed jaw are fitted for a vegetable diet. Length, 4 to 6 inches. California northward.
The Black Slug (A. niger, Cpr.) is dark, as a rule, with a narrow, long body, blunt in front, two inches long when crawling, an inch long or less when drawn up under shelter to rest.
Habitat.— Central California.
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