134 CRAYFISH, LOBSTERS, SPIDERS, AND INSECTS 



cephalothorax, great claws and all, is drawn out of the old 

 skin. Many times a good deal of difficulty is experienced 

 in pulling this part of the body from the case and the legs 

 are sometimes broken off. Finally, the abdomen is with- 

 drawn and the soft, unprotected body is now free from its 

 old investment. By the absorption of water, the body soon 

 swells to a size much greater than before. This is a critical 

 time for the crayfish, and it hides away in protected nooks 

 imtil the new skin absorbs lime and becomes hard. In the 

 process of molting, the fining of the gullet, stomach, and 

 intestine is also cast off. 



Economic importance of the crayfish. — Crayfishes are 

 used as food to a Umited extent in this coimtry and to a 

 considerable extent in Europe. They are also of some 

 benefit as scavengers. In the southern part of the United 

 States they often occur abundantly in cultivated fields 

 and cause serious damage to the growing crops. The 

 levees of the Mississippi River are sometimes weakened 

 by the holes of burrowing crayfishes. 



Crayfish, Lobsters, Shrimps, and Crabs 

 Glass. — Crustacea {body inclosed in a crust) 



Lobsters. — What has been said about the crayfish, ex- 

 cept with regard to distribution, applies essentially to the 

 lobster. Lobsters are found along the Atlantic coast from 

 Labrador to Delaware Bay, and from shallow water to a 

 depth of one hundred fathoms. They reach their greatest 

 size on the rocky shores in the cooler waters from Maine to 

 Labrador. They are much prized for food and are caught 

 in traps which are baited with fish offal of which the lob- 

 sters are very fond. It is now becoming rare to catch a 



