92 ARTHROPODS 



the web is for ? How do the spiders without webs get food ? 



(2) The webs of spiders are interesting objects of study 

 and may be seen almost anywhere, where special caution 

 is not taken to keep them away. Get a small bit of spider 

 web and put it under the low power of the microscope. 

 Can you tell its structure? Find a spider web out in the 

 open field or garden and study its structure ? Can you detect 

 anything like a plan in its formation ? If so make a drawing 

 of it. The web of the common geometrical, or garden 

 spider is a good one to study. 



(3) Have you ever seen spider webs flying in the air? 

 Where did they come from ? Some spiders can sail through 

 the air by throwing out a tangle of their web so that the 

 breeze will carry them with it. Are spiders injurious? 



(4) What are the enemies of spiders? Do spiders ever 

 protect themselves? In what ways? Is there a connection 

 between the colors of spiders and their safety? 



THE CENTIPEDE 



ScalapocryptopSt sp. 



General CnARACrERiSTics. — This animal is a harmless 

 one and may be examined either before or after it is killed. 

 It is commonly called the small centipede. 



How many divisions to the body Are all alike?' 

 Observe the appendages. How many ? Where located ? 

 Note the covering of dorsal and ventral sides. 



TiiE Head. — (i) Study the head from the dorsal side. 

 Do you find eyes? Antennae f Where are the antennae 

 located? How many segments in each? 



