A SPIDER. 



Phylum X, ARTHROPODA; class 5, ARACHNID A; order 6, ARANEIDA. 



HABITAT. Spiders are common in all lands except the very coldest, 

 where little life of any kind exists. The species are much less numer- 

 ous than in the insect class, but individuals are often very abundant. 

 Certain tribes or families live habitually in webs, which serve also as 

 snares for their prey. Some species live under bark and stones or 

 lurk in the concealment of foliage and flowers, while others prefer to 

 roam about obtaining their food by the chase. All live upon insects or 

 upon one another. 



Technical Note. Spiders have such soft bodies that they cannot be dried 

 and preserved like insects. If the season will permit, specimens 

 for class use may be obtained fresh from the field and killed in a 

 cyanide bottle. Otherwise use material preserved in alcohol or 

 formalin. Study with a hand lens or place on the stage of the dissect- 

 ing microscope, using a light or dark background as the case may 

 require. If the preserved material is used it is best to keep the 

 spider under water, as detail comes out clearer in this way than when 

 the body has become dry and the hairy covering matted together. 



A DORSAL VIEW. Members of the several family groups of spiders 

 differ markedly from one another in detail, so much so that it will be 

 necessary to keep within the bounds of the general in this outline. Any 

 one of the larger species of the Lycosidae, or Running Spiders, may be 

 easily obtained and will serve very well as a type. Note the following 

 relations and parts: 



a) A division of the body into two regions cephalothorax and 

 abdomen. Can you make out any traces of segmentation in 

 either region ? Is the cephalic part of the cephalothorax in any 

 way distinguishable from the thoracic part ? If the specimen 

 you are studying has not been hardened in a preservative fluid 



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