SPICE ISLANDS 



5497 



SPIDER 



SPICE ISLANDS, a name sometimes ap- 

 plied to the MOLUCCAS (which see). 



SPI'DER, a group of animals that are of 

 special interest because of their ability to spin 

 beautiful silken webs. The purpose to which 

 some of these dainty gauze structures are put 

 is known to every child who has learned the 

 poem beginning 



"Will you walk into my parlor?" said the spider 



to the fly. 

 " 'Tis the prettiest little parlor that ever you did 



spy; 



The way into my parlor is up a winding stair, 

 And I have many curious things to show when 



you are there." 

 "Oh, no, no," said the little fly, "to ask me is in 



vain, 



For who goes up your winding stair, can ne'er 

 come down again." 



Many an insect, however, is not so wary as 

 the fly of the poem, and meets its death in the 

 silken meshes. 



General Description. The spider itself is not 

 an insect, though zoologists at one time in- 

 cluded it among 

 the insecta. Ac- 

 cording to mod- 

 ern classification 

 spiders belong to 

 a class called 

 arachnida (which 

 see), to which be- 

 long also mites, 

 ticks and scor- 

 pions. Arachnids 

 have two body 

 divisions, a fore- 

 part consisting of 

 a united head and 

 thorax and an ab- 

 domen. In case 

 of the spider the 

 two parts are con- 

 nected by a slen- 

 der, flexible stalk. 

 Insects have three 

 body divisions. 



Another point 

 of difference is the 

 number of legs. 

 Insects have three 

 pairs, while 

 spiders and nearly all other arachnids have four. 

 The long, thin legs of a spider have seven joints, 

 and they end in tiny claws. In some species 

 the legs are so arranged that the animal can 

 move* in any direction forwards, backwards 



EXTERNAL VIEW OF 

 SPIDER 



1. Abdomen 



2. Fourth pair of legs 



3. Mandible 



4. Opening to breathing organ 



5. Opening to reproductive 



organs 



6. End of alimentary canal 



7. Eyes 



and sidewise. There are two other pairs of 

 appendages. These are in the nature of jaws, or 

 mandibles. The first pair end in pointed fangs 

 from which is ejected a poisonous secretion, 

 used in killing the spider's prey. So small an 

 amount is ejected that a human being bitten by 

 a spider usually suffers no more discomfort 

 than from a mosquito bite. The second pair of 

 jaws is used in grasping and holding the spider's 

 victim. 



Most spiders have eight eyes, borne on the 

 front of the head. Antennae, or feelers, are 

 lacking. The breathing organs consist of two 

 sacs, each containing several thin tissues ar- 

 ranged like the leaves of a book; slits on the 

 underside of the abdomen open into these sacs. 

 There are three pairs of spinnerets, small tubes 

 borne on the end of the body. From these 

 exudes a sticky liquid secreted by glands in the 

 abdomen. This substance forms the silky 

 threads of the web (see subhead below). The 

 mouth is merely a slit, as spiders feed on blood 

 sucked from other animals. The mouth is 

 joined to a sucking stomach by a short tube, 

 or oesophagus. 



The Weaving of the Web. The spider does 

 most of its spinning at night or in the early 

 morning. It raises its spinnerets in the air 

 and by gently pressing them against some ob- 

 ject causes the liquid silk to flow out. The 

 threads harden when they come in contact with 

 the air and unite into one strand. With this 

 thread the spider makes a suspension bridge, 

 tightening it with its claws and firmly cement- 

 ing it to a beam, leaf or wall. On several of 

 these strands is hung the gossamer net, which 

 is of various shapes. The web of the common 

 house spider consists of a number of crisscross 

 strands woven around the supporting spokes 

 and forming an irregular wall around a central 

 space. When any part of the web is broken 

 the spider immediately makes repairs, but after 

 it has spun several webs, its stock of silky fluid 

 is for a time exhausted, and it often takes pos- 

 session of the home of some other spider. 



Of all the wonderful structures made by the 

 lower animals, the orb web of the large black 

 and yellow garden spider is the most delicately 

 designed and skilfully made. This geometric 

 web consists of delicate spiral strands fastened 

 to spokes arranged like those of a wheel, and 

 is fixed to a branch or leaf with threads resem- 

 bling the ropes of a tent. The net is hung 

 vertically, that flying insects may hit against it 

 and be entrapped. The spider is never en- 

 tangled in its own web because it runs on the 



