2o 4 OTHER DENIZENS OF THE WOODS 



dages to the abdomen, which are found in nearly all the members of the group. 

 Among them, the spring-tails take their name from the fact that their forked 

 tail acts as a spring, which is kept bent when at rest, and suddenly released when 

 they jump. They have thread-like antennae with from four to eight joints, which 

 are generally shorter than the hairy abdomen. Many species live in large numbers, 

 among fallen leaves, under the bark of trees, in pits in the snow and other damp 

 situations. One of the prettiest, the hairy spring-tail (Podura villosa), frequents 

 bushes. It is an eighth of an inch long, yellowish red with black bands, and hairy, 

 particularly on the breast and antennae. The tree spring-tail (P. arborea), which is 

 not a third as long as this, and lives under the bark of trees, is black, with white 

 legs and tail. Groups of blackish brown, glistening spring-tails (Sminthurus 

 fuscus), only Jg- of an inch long, are often found on decaying wood. Another spring- 

 tail (S. signatus), about ^ of an inch long, lives among dead leaves, and is of a pale 

 green colour dotted with brown. 



With the Thysanura we complete our brief survey of the insects 

 Spiders 



of the woodlands, and with the spiders we enter on another class, that 



of the Arachnida. Spiders differ from insects in having eight in place of six legs, 

 and also in lacking a distinct head, the head and thorax being welded to form the 

 so-called cephalothorax. Most of them have eight eyes (some only six), which 

 are brightest at night. When full grown, each of the eight legs has seven joints, 

 varying in length, and the inner side of the claws is usually provided with bristles 

 or combs for the management of the thread during the act of spinning. Spiders 

 lay eggs, from which the young hatch out in the fully adult shape, although they 

 moult several times before they are mature. During moulting-time they replace 

 broken limbs and repair damages generally. Most spiders live on land, although 

 a few are aquatic. All prey upon living insects, especially those with wings, 

 biting them first with their jaws, then killing them with the poison which flows 

 from a fang in the second segment of the mandibles, and finally chewing and suck- 

 ing the bodies. They are able to fast for long periods, but at other times eat a 

 great deal, and do not even spare their fellows when shut up with them. Spiders 

 dwelling in the open air generally die at the beginning of winter, but individual 

 members of some large species may live for years, and pair several times, although 

 this holds good only for the females. Young spiders are often found underneath 

 the bark of trees in a cocoon, the material of which is furnished by silk-glands 

 occupying the greater part of the spider's abdomen. The silk consists of a tough 

 sticky matter, which instantly hardens in the air, and is drawn out of six or eight 

 spinning mammillae, open at the back, and perforated at the tip like sieves. Each 

 of these contains from a hundred to four hundred tubes, from which issue the 

 threads, which are so fine that several thousands are necessary to make up the 

 thickness of one human hair. Of these threads the spiders make their webs and 

 cocoons. In September and October the threads are often noticed drifting with a 

 spider attached to them, their flights often extending for some distance, so that 

 they have even been met with at sea many miles from shore. They end 

 these flights at will by twisting up the thread until it has not sufficient buoyancy 

 to support its weight. When placed on the palm of the hand, spiders raise their 



