47 6 Handbook of Nature-Study 



of the head is the mouth, guarded by two mandibles, each ending in a 

 sharp claw, at the tip of which the poison gland opens. It is by thrusting 

 these mandibles into its prey that it kills its victims. On each side of the 

 mandible is a palpus, which in the males is of very strange shape. The 

 eyes are situated on the top of the head. There are usually four pairs of 

 these eyes, and each looks as beady and alert as if it were the only one. 



The spinning organs of the spider are situated near the tip of the 

 abdomen, while the spinning organ of the caterpillar is situated near its 

 lower lip. The spider's silk comes from two or three pairs of spinnerets 

 which are fmgerlike in form, and upon the end of each are many small 

 tubes from which the silk is spun. The silk is in a fluid state as it issues 

 from the spinnerets, but it hardens immediately on contact with the air. 

 In making their webs, spiders produce two kinds of silk, one is dry and 

 inelastic, making the framework of the web; the other is sticky and elas- 

 tic, clinging to anything that it touches. The body and the legs of 

 spiders are usually hairy. 



LESSON CX 



COBWEBS 



Leading thought The cobwebs which are found in the corners of ceil- 

 ings and in other dark places in our houses, are made by the house spider 

 which spins its web in these situations for the purpose of catching insects. 



Method The pupils should have under observation a cobweb in a 

 corner of a room, preferably with a spider in it. 



Observations i. Is the web in a sheet or is it a mass of crisscrossed, 

 tangled threads? How are the threads held in place? 



2. What is the purpose of this web? Where does the spider hide? 

 Describe its den. 



3. If a fly becomes tangled in a web, describe the action of the spider. 

 Does the spider eat all of the fly ? What does it do with the remains ? 



4. If the spider is frightened, what does it do? Where does the 

 silken thread come from, and how does its source differ from the source of 

 the silken thread spun by caterpillars? 



5. Imprison a spider under a tumbler or in a vial, and look at it very 

 carefully. How many legs has it? How does the spider differ from 

 insects in this respect ? How many sections are there to the body ? How 

 does the spider differ from insects in this respect? 



6. Look closely at the head. Can you see the hooked -jaws, or fangs? 

 Can you see the palpi on each side of the jaws? Where are the spider's 

 eyes? How many pairs has it? 



When the tangled cobweb pulls 



The cornflower' s cap awry, 

 And the lilies tall lean over the wall 

 To bow to the butterfly 

 It is July. 



SUSAN HARTLEY SWETT 



