THE SPIDER. 21 



THE SPIDER. 



Spiders are best preserved in alcohol, as they shrink in 

 drying. 



1. The anterior division of the body is the cephalo- 

 thorax, or united head and thorax. 



2. The large posterior division is the abdomen, 



3. How many legs are there? To what are they at- 

 tached? How many segments are there in each? 

 Examine the feet under a microscope. Make a draw- 

 ing of one of the feet. Can a spider climb out of a 

 tumbler ? Compare it with the beetle in this respect. 



4. With a dissecting needle pry apart the mandibles, 

 at the front of the head. Make out the fine, spine- 

 like, curved poison fang at the lower end of each 

 mandible. 



5. Back of the mandibles find a pair of small jaws, the 

 maxillae. 



6. To the maxillae are attached a pair of jointed append- 

 ages, resembling a pair of legs, the maxillary palpi. 



7. With a lens look for the simple eyes above the jaws. 

 How many are there, and how are they arranged ? 



8 With a lens examine the spinnerets at the posterior 

 end of the abdomen. With a pair of forceps hold a 

 live spider by one leg, and watch the beginning of 

 spinning. Highly magnified, the spinnerets appear as 

 blunt protuberances arranged together in pairs, and 

 capable of being contracted or expanded. These 

 spinnerets are covered with hundreds of jointed hairs, 

 which are perforated and through which the web- 

 forming material issues. This material is fluid, and 



