This book is designed to make the reader acquainted with The front half of a spider's body, called the cephalothorax, contains in one piece the head and thorax, the only outward division between them being shallow grooves from the middle of the back to the front legs. In the middle of the cephalothorax is usually a groove or depression, under which, inside, is a muscle that moves the sucking apparatus by which food is drawn into the mouth. At the sides of the thoracic part are four pairs of legs, and on the head part are a pair of palpi and a pair of mandibles. The legs have seven joints: (1) the coxa, the thick basal joint, having little motion; (2) the trochanter, a short joint moving very freely on the end of the coxa; (3) the femur, the largest joint of the leg, moving with the trochanter in all directions; (4) the patella, moving up and down on the end of the femur; (5) the tibia, joined closely to the patella and moving with it up and down; (6) the metatarsus; and (7) the tarsus, moving together on the end of the tibia. The palpi are like small legs and have one less joint than the walking legs. The mandibles are close together at the front of the head (fig. 2). They are two-jointed, the basal joint stout and the end joint or claw slender and sharp-pointed. The claw has near its point a small hole, which is the outlet of the poison gland. The poison kills or disables the insects which are captured by the spider. Its effect on the human skin varies in different persons; sometimes it has no effect at all; oftener it causes some soreness and itching like the stings of mosquitoes and bees, and cases have been known in which it caused serious inflammation which lasted a long time. Spiders seldom bite, and only in defense, the bites so commonly charged to them being often the work of other animals. On the front of the head are the eyes, usually eight in number, differing in size and arrangement according to the kind of spider. The sight of spiders is distinct for only short distances. Spiders of middle size can see each other, and the The hinder half of the body, the abdomen, is connected with the cephalothorax by a narrow stem (fig. 1). It has at the hinder end the spinnerets, three pairs of appendages having at their ends a great number of microscopic tubes through which the thread is drawn out. When not in use the spinnerets are folded together, so that the smaller inner pair are concealed. The thread of spiders resembles that spun by caterpillars in making their cocoons, and can be manufactured in the same way into silk cloth. The spider's thread is composed of a great number of finer threads passing from the body through separate tubes and uniting into one before they have time to dry. This can be seen by examining the attachments of spiders' threads to glass. All the spinning tubes are not alike, but on certain parts of the spinnerets are larger or differently shaped tubes, and these are the outlets of glands of different kinds in the spider's abdomen, and are used in making different kinds of threads for certain parts of the webs, nests, or cocoons. In front of the spinnerets on the under side is a small opening to the tracheÆ, or air-tubes (fig. 1). At the front of the abdomen on the under side is a transverse fold of the skin, at the ends of which are the openings of the air-sacs or The colors of spiders are partly in the skin itself and partly in the hairs and scales that cover it. Almost all spiders are covered with hair of some kind, but in some species it is so fine and short that it has little effect on the color. In others the skin is entirely covered with hairs of various lengths and sometimes with scales somewhat like those of butterflies, flattened and feathered or toothed on the edges. The colors of spiders are very varied, and in many species, especially of the jumping spiders, as brilliant as those of butterflies. The most common colors are grays and browns, resembling the ground or plants and stones among which the spiders live. Sometimes the color is uniform all over the body, except that it is a little darker toward the head and the ends of the feet. The most common marking is a spot on the front of the abdomen over the spider's heart, sometimes merely a translucent part of the skin and sometimes a definite color spot darker in the middle and outlined with a lighter shade or white. The hinder half of the abdomen is often marked with several pairs of spots, becoming smaller toward the end, and these spots may be united into a pair of stripes or a more complicated pattern. (See figures.) The legs are often marked with rings of color, Spiders live in all kinds of places. Certain species are attached to houses and seldom found far from them, and many of these occur over a large part of the world. The light webs in the corners of rooms are chiefly the work of Theridium tepidariorum (p. 112), occasionally of Steatoda borealis (p. 119) and Steatoda triangulosa (p. 121). In cellars the thin webs about the stairs and shelves are those of the long-legged Pholcus phalangioides (p. 129) or of Linyphia nebulosa or minuta (pp. 144, 145), and the thick flat webs in corners and between the beams are those of Tegenaria derhamii (p. 96). On the outside of houses live two jumping spiders, the most common being Epiblemum scenicum (p. 60), a small gray species the color of weathered wood, and the other, Marptusa familiaris (p. 61). Some of the round-web spiders live in great numbers about houses. The three brown species, Epeira sclopetaria (p. 160), patagiata, and strix, hide in cracks and at night make their round webs in porches, barns, and bridges. In the northern part of the country Epeira cinerea (p. 165) has the same habit. Epeira globosa (p. 174) is often found on the outside of houses, and so are Zilla atrica and Zilla x-notata (p. 185). Amaurobius ferox (p. 215), a large imported species, is sometimes found in cellars, and several Dictyna (p. 206) live in great numbers on the outside of houses, in corners of windows, under the edges of shingles, or in cracks of walls, spreading their webs wherever there is room for them and gathering dust so that they often make a distinct spot on the wall. In the southern states Filistata hibernalis (p. 220) is one of the most common In the summer, plants of all kinds from grass to trees are full of spiders. The Lycosas (pp. 68 to 84)run among the short grass. The small species of Linyphia (p. 134) and Erigone (p. 148) make their flat webs close to the ground among small plants. Linyphia marginata, communis, coccinea, and phrygiana make theirs among plants and rocks, a foot or two above the ground. The Theridiums (p. 110) live between leaves and on the ends of twigs, covering them with webs that only show when the dew is on them. Agalena nÆvia (pp. 91 to 95) makes its flat webs on the grass and anywhere else where it can find a place to fasten them. The jumping spiders (p. 41) run about for their prey on plants, and some of them have silk nests among the leaves. The Misumenas (p. 25) live among flowers and wait for insects to alight within reach. The webs of Dictyna (p. 206) are commonest on the ends of grass and twigs, and are known by the dust that they gather. The round-web spiders mature in the middle of the summer, and The marshes are the home of great numbers of spiders. The Tetragnathas (p. 198) live there, especially along the streams and ditches. Epeira gibberosa (p. 175) and placida (p. 176) make their horizontal and oblique webs among the tall grass in open places. The two species of Argiope (pp. 193 to 198) swarm in marshes and open fields and in autumn become conspicuous by their size and bright colors, and when they disappear leave over winter their brown cocoons (pp. 197, 200) fastened to the grass. The moss and dead leaves in the woods are alive with spiders; even in summer some species always live there, and in winter the young of those that in warm weather live among the bushes find shelter where they can remain torpid through the cold season without freezing. The eggs of spiders are covered with silk, forming a cocoon which varies much in shape and color in different species. Some spiders hang it in the web, others attach it to plants or stones, and others carry it about with them either in the mandibles or attached behind to the spinnerets. The young remain in the cocoon until they are able to run about, and after coming out of the cocoon keep together for a short time, sometimes in a web which they make in common, sometimes in a nest made by the mother, and in some species on the mother's back, but they soon scatter and hunt their own food or make cobwebs, according to the habits of the species. Different kinds of spiders mature and breed at different times of the year, most of them living only one season. Those that mature late, like Agalena nÆvia and Argiope, pass the winter as eggs, while those that mature early, like Epeira sclopetaria and Lycosa nidicola, pass the winter half grown. Some species, like Theridium tepidariorum (p. 112), breed several times in the year, and old and young are found at all seasons. The spiders are naturally divided into two groups of families: (1) the hunting spiders, which run on the ground or on plants, catching insects wherever they find them, or waiting among leaves and flowers until insects come within their reach; (2) the cobweb spiders, which make webs to catch insects and live all the time in the web or in a nest near it. The hunting spiders include: (1) the DysderidÆ (p. 22), a few species with six eyes only and with four breathing holes at the front end of the abdomen; (2) the DrassidÆ (p. 1), or ground spiders, which live among stones and dead leaves or among plants, making tubular nests and flat egg cocoons but no cobwebs; (3) the ThomisidÆ (p. 24), the flat and crab-like spiders living on plants or under bark and stones; (4) the AttidÆ (p. 41), the jumping spiders, with wide heads and large front eyes, many of them brightly colored and active in their habits; (5) the LycosidÆ (p. 67), the long-legged running spiders, living on the ground and, a few of them, in holes and carrying about their round egg cocoons attached to the spinnerets. The cobweb spiders include: (1) the AgalenidÆ (p. 91, making flat webs on grass or in corners of houses, with a tube at one side in which the spider lives; (2) the TherididÆ (p. 107), round spiders with flat or irregular webs in corners and on plants; (3) the LinyphiadÆ (p. 134), with flat webs, small spiders of a great number of species living near the ground Cobwebs are of four principal kinds: 1. The flat webs, closely woven of long threads crossed by finer ones in all directions and connected with a tubular nest where the spider hides, and from which it runs out on the upper side of the web after insects that may fall upon it. These are made by Agalena and Tegenaria (pp. 91 to 104). 2. The net-like webs, made of smooth threads in large meshes, sometimes in a flat or curved sheet held out by threads in all directions. The spider lives on the under side, back downward. These are made by TherididÆ and LinyphiadÆ (pp. 107, 134). 3. The round webs, made of threads radiating from a common center and crossed by circular loops and spirals, part of which are adhesive. 4. The webs of the CiniflonidÆ, composed in part of loose bands of silk (p. 205). The simplest and best way to preserve spiders for examination is to put them in alcohol. It kills them immediately and keeps their form and markings and, to a great extent, their colors. They may be kept alive for a few days in glass bottles or jars. It is not necessary to make holes in the covers, or to feed the spiders often. They need water, and this can be furnished them conveniently by putting a piece of wet paper or rag in the bottle. If one wishes to find what spiders live in his neighborhood, they must be looked for at all times and in all kinds of places. The house and cellar should be looked over and the spiders watched until they are fully grown. The outside of the house and fences should be looked over occasionally in the same way, only those spiders being taken that are full grown, unless they Spiders should be looked for in the same way in grass, by creeping along on the ground or by sitting down and watching until something walks into view; or the grass and weeds may be swept with a cotton bag, fastened on a hoop like a dip net, with a short handle, and the spiders picked out with a dry bottle from among the leaves and insects that will be gathered In the following pages a general description is given of each family, followed by descriptions of the species belonging to it, with a figure of each species placed as near as possible to the description. In some cases, where the genera are large and well defined, separate descriptions are given of each genus, but where the genus is not easy to distinguish or represented by only a few species, there is no separate generic description, and the species are placed next to those of other genera to which they are most closely related. If the names of spiders are known, they can readily be found by the index at the end of the book. If information is sought about an unknown spider, the illustrations through the book furnish the most convenient index, as the general form and proportions of spiders and the arrangement of their eyes usually show to what family they belong. The ground spiders and those without cobwebs are described first, and the sedentary species living in webs in the last half of the book. Readers unfamiliar with the subject are advised to read first the descriptions of the families and compare with them the spiders that they find in their own neighborhoods. The figures are in most cases enlarged for the sake of distinctness, and spiders of much smaller size must be looked for. THE COMMON SPIDERS |