SPIDER 265 cording to Leeuwenhoek, it takes 4,000,000 of the extremely delicate threads from the thou- sands of spinnerules to make a filament as large as a human hair ; each thread of the spider as used in the web is made up of thousands of smaller ones ; one or all the spinnerets may be used as occasion requires. Attempts have been made to render the silk of the spider avail- able for manufacturing purposes, but with lit- tle success. (See COBWEB, and SILK SPIDER.) Spiders are eaten by many barbarous tribes of men, as the American Indians, S. Africans, and Australians; they also supply abundant food to many birds, reptiles, and carnivorous insects. They are affected and frequently de- stroyed by parasitic mites, and their eggs serve to nourish the young larva? of several species of ichneumon flies; the smallest puncture in the chest or abdomen is fatal from the impos- ibility of arresting the escape of the nutrient luids; their colors fade rapidly after death, jven in preservative liquids. A single wound >m a spider will soon kill the domestic fly ; the large crab spiders of South America (my- gale) leap upon and destroy humming birds and creepers, and produce dangerous and occasion- ally fatal symptoms in debilitated persons ; every physician knows that even the bite of smaller spiders of temperate climates may >ierce the skin in certain localities, and cause painful irritation. For descriptions and figures of the species of the United States see papers by N. M. Hentz in vols. iv., v., and vi. of the " Boston Journal of Natural History " (1841- >7), now in course of republication, with fig- ures by the same society (1875). The genus mygale (Walck.) contains the largest of the spiders, of dark colors, nocturnal, living in dleries which they make in the ground, in jfts of trees, crevices in rocks, or among ives. The crab or bird spider of South imerica (M. avicularia, Walck.) is about 3 in. long, its legs extending over a space of 8 or 10 the body is very hairy and blackish, and ends of the feet are reddish ; it is very )owerful, jumping upon and killing small birds ; it spins no web ; its cell is in the form of a pointed tube, of a white firm tissue. There are some large species in the southern states, feed- _ principally on the large orthoptera, believed by the Indians to possess valuable medicinal properties, and eaten accordingly. A large species (M. Hentzii) in Texas is called there ta- rantula ; other species in California are called trap-door spiders, from their hollowing a more or less conical nest, about 3 in. long and an inch in diameter, in the clayey soil ; the nests are lined with 'silk, with an accurately fitting lid, so arranged that the inmate can firmly hold it down against ordinary enemies ; the cover outside so nearly resembles the surround- ing earth in color and roughness as to be rec- ognized with difficulty. For an account of the curious devices in the interior arrangement of these nests, see "Proceedings of the Boston Society of Natural History" for 1875. The species of the genus lycosa (Latr.) are well called wolf spiders, for they are the most sav- age, voracious, and quarrelsome of the family ; they make no web, but prowl on the ground by night, running very fast, and hiding in nat- Wolf Spider (Lycosa fatifera). ural or artificial holes in the ground, which they strengthen with silk ; the females carry the cocoon attached to the posterior part of the body, and defend it with the greatest cour- age, some guarding it under stones ; the young when hatched climb on the abdomen of the mother, giving her a monstrous appearance, and are said finally to devour her. One of the largest and most common species is the L. fatifera (Hentz), about 1-J- in. long, hairy, and bluish black ; it is as large as the tarantula of Europe, which belongs to this genus, and is not uncommon in Massachusetts ; it must rarely bite persons, from its habits and haunts, though its poison may produce ill consequences if introduced under the skin, not however to be compared with those from the mygale of the tropics ; it is very savage and tenacious of life. The genus attus (Walck.) includes the small species commonly called jumping spiders ; they make no web, wander in search of prey, and cast the skin and hibernate in silken-valved recesses ; they are common in summer on walls and windows in the sun, walking by jerks, crawling stealthily up to flies, and jumping with rarely failing accuracy when near enough. The best known jumping spi- der in New England is the A. familiaris (Hentz), about % in. jumping Spider long, pale gray and hairy, the (Attus familiaris). abdomen blackish with a gray- ish angular band ; it is very common in houses, dwelling in cracks on the outside, and wan- dering about in the sun in search of food ; before leaping at a fly, it fixes a thread to secure itself from falling. It is widely dis-
