266 SPIDER Common House Spider (Tegenaria mediclnalie). tributed. Its backward gait is as rapid as its forward. The long-legged spider (pholcus Atlanticus, Hentz) is about in. long, with a narrow body and very long slender legs, which are easily separated at the will of the animal when seized by them ; the color is pale gray ; it is common in corners of dark and rare- ly used rooms, in cellars and churches, spinning a very loose web crossed in all directions, which is very rapidly shaken when touched ; the eggs are car- ried in the jaws, envel- oped in a silken bag, and about 200 young are rolled in a ball not larger than a pea ; the food consists of very small insects, though they eagerly devour each other, especially when young ; they are favorite food for wasps, who store their cells with them as a provision for their young. The European representative is the P. phalangioides (Walck.). The common house spider {tegenaria medicinalis, Hentz) is found in every house and cellar in the land ; the cheliceres are moderate, and the fourth pair of feet the longest ; the upper two spinnerets are remarkably larger than the others, and the four anterior eyes in a line curved backward. It is sedentary, making in an obscure corner a large and nearly horizontal web, with a tubular hab- itation at the upper part ; it is not quite an inch long, varying in color from pale brown to bluish black according to the absence of light in its retreat, with a dark band on each side of the thorax, and the abdomen and feet varied with blackish ; the specific name is derived from the use formerly made of the web in cases of fever. In epelra (Walck.) the web is either vertical or inclined, and the threads are arranged in a more or less regularly geometri- cal manner, radiating from the centre, where the animal remains, ac- cording to the absence of disturbing causes. ' The common epe'ira (E. vul- gari*, Hentz) is less than an inch long, with a full body, gray with blackish abdomen, with winding white marks and a white cross in the middle ; it may almost be said to be domesticated, its geomet- rical web being so often met with near the win- dows of houses. The webs of the spider, like the cells of the bee, are not geometrically per- fect; their irregokritj can generally be de- tected even by the unassisted eye. The long- round-bodied spider, commonly called " father long-legs," is one of the trachearian Common Epoira (Epeira vulgaris). SPIDER CRAB arachnids, so named from the respiratory or- gans being radiated tracheae, receiving air through two stigmatic openings ; it is the har- vest spider (phalangium cornutum, Linn.) in Europe, and an allied species in the United States. The eyes are two ; the mandibles end in double pincers ; the legs are eight, slender, and when separated from the body exhibit signs of irritability for some time. They are harmless, preying upon mites and small in- sects, and are very common in the fields. Many small spiders fly about on their silken threads, carried far by currents of wind. Of the arachnida, the scorpions appeared first in the carboniferous epoch, and the true spiders in the Jurassic age. See " American Natural- ist," vpls. v. (May, 1871), vi. (March, 1872), and viii. (October, 1874), for descriptions and figures. See also various articles on spiders by Dr. Burt G. Wilder, in " Proceedings of the American Association for the Advancement of Science," 1873, and the "Popular Science Monthly," April, 1875. For further details see chap, xviii. of Rennie's " Insect Architec- ture," the works of Kirby and Spence, and particularly the Histoire des insectes apt&res (Nouvelles suites d Buffori), by Baron Walcke- naer (vols. i., ii., and iii., 8vo, Paris, 1837-' 44). (See MITE, SCORPION, and SILK SPIDER.) SPIDER CRAB, or Sea Spider, the name of several species of ten-footed short-tailed crus- Spider Crab (Maia squinado.) taceans of the crab family, and more particu- larly of the libinia canaliculata of North America and the maia squinado of Europe. In L. canaliculata (Say) the thorax is densely hairy, with spines on the borders and on the back ; the rostrum is grooved at the tip and channelled between the eyes ; the anterior feet are unarmed and granulated, the hands elon- gated, and the fingers white at tip. The body is convex and heart-shaped, 4 in. in diameter, the long legs spreading over 12 to 16 in. ; the eyes small and very short ; it is blackish green,
