22 PRACTICAL ZOOLOGY. 



somewhat like the white of an egg. Escaping from 

 the body, through hundreds of these 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 often be separated just as the fibres of a rope 

 may be pulled apart. 

 9. Besides tracheae, spiders have a so-called lung, com- 

 posed of several leaves, into which blood flows, and is 

 thus aerated. 



Place the description of the spider alongside the list of 

 characters common to insects, and note what features are 

 common to the spider and all the insects ;" also the points 

 wherein they differ. 



Spiders belong to the class Arachnida. Is the young 

 spider, when first hatched, like the adult? Study the 

 habits of spiders, and their methods of spinning their webs 

 and capturing insects. 



Read Emerton's " Spiders, their Structure and Habits," 

 and the chapters on spiders in Morse's "First Book of 

 Zoology," Packard's " Zoology," and Packard's " Guide." 



THOUSAND LEGS. 



One form of thousand legs, commonly found under the 

 bark of dead stumps and logs, is well known by its cylin- 

 drical body, by its numerous, short, hair-like feet, and by 

 its habit of coiling its body into a spiral when disturbed. 



