296 TEXTBOOK OF ZOOLOGY 



in number and arranged in two rows, but in this family there are 

 only two tarsal claws. They differ from the wolf spiders in that the 

 body is much longer than wide and flattened slightly on the back. 

 This is one of the large families of spiders. Drassus negledus is a 

 representative species. 



5. Attidae, jumping spiders. Members of this family attract atten- 

 tion by their jumping and bright coloration. They live on fences, 

 buildings, plants, and on the ground. They do not spin webs for the 

 capture of prey but only for their protection and cocoons. The eyes 

 of this group are most distinctive. They are arranged in three rows, 

 occupying an area on the cephalothorax known as the ocular quad- 

 rangle. The eyes on the front row are the largest. The males and 

 females differ considerably in size and structure. This family is 

 world-wdde in distribution. It is represented by three hundred and 

 fifty species in America north of Mexico. Some of the common species 

 of our fauna are: Phidippus worhmanii; P. formosus; Icius similis; 

 EuopJirys monadnock; and Salticus senicus. 



6. Argiopidae, the orb-web spiders. The spiders of this family build 

 rather large typical webs for the purpose of capturing their prey. 

 After building the web they lie in wait for some insect which may 

 serve for food to become entangled in it. This is a large family, the 

 members of which have eight eyes, and three claws on the tarsus. 

 They are confined to suitable places on vegetation, buildings, fences, 

 and holes, where they construct their webs and then remain near by 

 to watch them. Some of the common species of this family are Tetrag- 

 natha lahoriosa; T. extensa; Metargiope trifasciata; Neoscona ben- 

 jamina; and Aranea gemma. 



Most of the species of Tetragnatlia are found in moist places ; they 

 build their webs over running water. Their bodies are round and 

 long. Metargiope trifasciata is the common garden spider, found in 

 the fall of the year in potato, tomato, and beet fields. It has a silvery 

 white color and is about an inch in length when full grown. 



7. Aviculariidae, the tarantulas. Representatives of this family are 

 confined to the south and southwestern United States. They are 

 large, hairy, black spiders with eight eyes and chelicerae projecting 

 forward. The trap-door spiders live in tunnels dug in the ground 

 and provided with a hinged door which closes the entrance to the 

 tunnel so perfectly that it is almost impossible to locate the tunnel. 

 The tarantulas, which are large nocturnal species, live under rocks, 



