thorax. The hinder region is called the abdomen. Instead of having a separate head, as in true insects, the spider has its head and thorax combined, and hence this part is called the cephalo-thorax, a compound word meaning head-thorax.

FIG. 105.-COMMON GARDEN SPIDER.-A, as seen from above; B, as seen from below; p, Palpi; m, Mandibles; 8, Spinnerets from which the Spider's Thread issues.

102. The spider has four pairs of legs, instead of three pairs of legs as in the true insects. Projecting in front are a pair of jointed feelers called palpi (see Fig. 105, p). These look very much like legs, and in very young spiders can scarcely be distinguished from them.

FIG. 106.-SIDE-VIEW OF COMMON GARDEN SPIDER.-C, Cephalo-thorax; A, Abdomen; 1, 2, 8, 4, First, Second, Third, and Fourth Pairs of Legs; s, Spinnerets; m, Mandibles; p, Palpi.

The mouth is armed with a pair of jaws which are attached above the mouth and hang down in front, at the end of which are the poison-fangs. With these they are enabled to secure and kill the flies and other insects upon which they feed. The following figure represents the jaws

FIG. 107.-FRONT PORTION OF COMMON GARDEN SPIDER GREATLY ENLARGED, showing, pp, Palpi; m, Mandibles; ll, a Portion of the First Pair of Legs, and above, the Front of the Cephalo-thorax, with the Eight Eyes upon it.

Directly behind the mandibles, are two smaller jaws, called maxillæ (see Fig. 108), which aid in crushing the food and arranging it for the mouth.

FIG. 108.-INNER JAWS, OR MAXILLE, OF A COMMON GARDEN SPIDER.-The first Joints of the Palpi are seen also.

The spider has eight eyes, situated on the front part of the cephalo-thorax. They look like little black beads, and in

large spiders can be easily seen without the aid of a magnifying-glass.

103. The abdomen has little appendages at its hinder end called spinnerets, and from these the spider produces the thread with which it builds its nests and nets, the nets being commonly called spiders' webs.

Highly magnified the spinnerets appear as blunt protuberances arranged together in pairs, and capable of being contracted or expanded. These spinnerets are covered with hundreds of jointed hairs which are perforated and through which the web-forming material escapes. This material is fluid and something like the white of an egg. Escaping from the body, through hundreds of these minute openings, the strands of this fluid dry almost instantly, and, uniting, form the delicate, yet comparatively strong, thread of the spider. Thus it will be seen that the thread of the spider is composed of hundreds of strands, which may be often separated just as the fibres of a rope may be pulled apart. Under the microscope the posterior end of the abdomen with the spinnerets looks like this.

FIG. 109.-SPINNERETS OF A SPIDER.-t, one of the Tubular Hairs from the Spinnerets, highly

magnified.

104. As the thread issues from the spinnerets, the spider guides it with its hind pair of feet, and these are curiously adapted for the purpose not only of holding and guiding the thread, but also of enabling the spider to run rapidly across its nets without getting entangled, while other animals become helplessly ensnared in attempting the same thing.

The ends of the legs terminate in three claws, a pair of larger ones generally notched like a comb, and a third one like a spine which acts as a thumb. Other notched spines or hairs also aid in securing a hold upon the web, and even if these fail to secure a footing, the leg itself is covered with long stiff bristles pointing downward which are sure to catch in the web. The two large notched claws, as well as the other claw and spines, are highly polished, and consequently present no roughened surface to which the thread will adhere.

The following figure (Fig. 110) represents the end of a spider's leg magnified, showing the arrangement of hooks and claws.

t m 0

FIG. 110.--END OF A COMMON GARDEN SPIDER'S LEG MAGNIFIED.-o, Outer Claws; m, Middle Claw; t, Toothed Hairs.

105. By observing the spiders which build their nets across the openings of windows and in other convenient

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places, and while at work, they may be seen to use their hind-feet in apparently drawing out the thread as it were from the spinnerets. It will be observed that the thread issues in a broad band, and, when these spiders are sluggish, their thread may be caught on the end of a pencil by gently rubbing the spinnerets with it, and then by withdrawing the pencil the thread may be reeled off.

The various kinds of nets are adapted to entrap the spider's food, which consists of flies and other insects.

Certain kinds of spiders do not build nets, but go in search of their prey by stealthily creeping up and pouncing upon it unawares.

It is a very interesting sight to watch the little black-andwhite spider (so common on the sides of houses) slyly approach a fly which has alighted near it. If the spider is on the side of a window-sill and a fly has alighted near it, the spider instantly turns round, facing the fly, cautiously and very slowly moves backward, till it gets on the upper side of the window-sill and out of sight, when it rapidly approaches, now and then peering over the edge of the sill, to see where the fly is, and, finally getting directly above the fly, it gathers its legs for a jump, securing its thread to the window-sill at the same time, and then with a sudden spring seizes the fly in its jaws. Sometimes the insect is much larger than the spider, and flies away, with the spider tightly clinging to it; the thread, however, holds fast, though sometimes run out to the length of a foot or more. Soon the poison of the spider takes effect, and the fly gradually weakens, and ceases its strug