110 



CRABS AND INSECTS. 



air, hardens and forms a silken thread (Fig. 131, s) that is 

 seemingly inexhaustible. 



FIG. 131. Parts of a spider, i, Under part of a spider's body : /, thorax, or 

 chest, from which the eight legs spring, and to which the head is united 

 in one piece ; _/, fangs ; /, palpi, or feelers, attached to the jaws ; a, ab- 

 domen ; b, breathing-slits ; s, six spinnerets with thread coming from 

 them. 2, Front of spider's head : ^, eyes ; /, palpi ; /, front legs ; //, 

 hasp of fangs ; /", poison-fangs ; /, outer jaws. 



NOTE. Professor Wilder wound several miles of silk from the 

 Southern Nephila phimipes, the largest spider in the United States 



(Fig. 130). In the Pacific 



A B C is'ands an Eptira spins a web 



strong enough to catch birds. 

 Professor Moseley found a 

 finch entangled in one of 

 their webs. Some spiders 

 spin a web that bears them 

 away through the air like 

 a balloon. The Dolomedes 

 builds a raft of leaves and 

 silk, and launches it in search 

 of food. Many mimic their 



surroundings, while others communicate so rapid a movement to their 

 webs as to become invisible. The Salticus leaps through the air after 



FIG. 132. Spiders' nests of different kinds, 

 containing eggs. A and C are common 

 nests in sheds and barns ; B was found 

 under a board in the field -the part 

 containing the eggs, stands upon a stalk. 

 (After Morse). 



