spider belongs to the Theridudae, or Comb-footed Spiders, which differ from 

 all other families of spiders by the presence of a "comb" or regular row of 

 serrated bristles along the inner side of the last segment of each hind leg. This 

 comb is discernible only under a lens. The black widow may be distinguished 

 from the other Comb-footed Spiders by having the eyes on each side well 

 separated rather than adjacent, by its large globose abdomen and by its jet-black 

 color. Most of these spiders have red and yellow markings on the abdomen, the 

 most characteristic being an hour-glass shaped patch on the under side. These 

 m.arkings vary, however, and may be completely absent. Adults are about one- 

 quarter to one-half an inch long. They are most abundant in the southern 

 states, but may occur anywhere in the United States. 



In most species of spiders the male is considerably smaller than the female 

 and is a poor spinner. He may occasionally be found living as a dependent at 

 one edge of the female's web and taking the leavings of her feasts. The female 

 usually shows great solicitude for her young. A large mass of eggs is usually 

 securely enclosed in a large "nest'' of silk, which may be spherical or discoidal. 

 In most species the case is fastened in some sheltered location or placed under 

 a rock or loose piece of bark. A few species carry their egg cases with them, 

 either attached to the abdomen or clutched by the mouth appendages. 



The most spectacular of the spider group are those commonly called tarantu- 

 las, many of which are dangerously poisonous. The most famous tarantula, the 

 effects of whose bite could supposedly be warded off only by performing a 

 vigorous dance which came to be called the tarantella, is a native of Europe. 

 The large, hairy spiders of the southern and southwestern states have long at- 

 tracted wide attention. The most remarkable of these are the trap-door spiders, 

 which excavate in the soil deep burrows topped by hinged lids, line them with 

 a plaster of saliva and earth, and usually add an additional lining of web. The 

 members of another group are called the running tarantulas or bird spiders. 

 They are the largest of the tarantulas, one South American species having a 

 body two inches long and a leg span of seven inches. Some of the early descrip- 

 tions of this spider record its ability to capture small birds. Although its usual 

 fare consists of insects, and the capture of birds is probably rare, the more dra- 

 matic event was naturally more noted and gave the spider its common name, 

 as well as the generic name of Avicularia. A third group of the tarantulas spin 

 webs. One of the most peculiar of these is the purse- web tarantula, which not 

 only lines its burrow at the base of a tree with web, but also extends the web as 

 a straight tube for about a foot above ground against the tree trunk. When 

 some unwary insect uses this conveniently placed ladder, the spider runs up 

 the inside of the tube and bites the unlucky insect through the web. It then cuts 

 the web, sucks the juices of its prey, and patches up the trap ready for the next 

 comer. 



204 



