286 LIVING THINGS IN THEIR ENVIRONMENT 



The female carries her eggs on the under side of the jointed 

 abdomen. Crayfish must be kept by themselves, for they, 

 like the turtle, will eat the living things in your aquarium. 



Ab. 



The crayfish (A) antennae or feelers ; (M) the line points to the mouth ; (Ch) 



the chelipeds or big pincers; (E) the eyes on stalks; (CF) the caudal fin or tail; 



(CP) the cephalothorax or head and body part, and (Ab) the jointed abdomen. 



How many pairs of legs has the crayfish ? How many joints in the abdomen ? 



Many other crustaceans will be found : rarely, small 

 shrimps, and more frequently, flattened "sow bugs," 

 " water fleas/' and copepods. Many smaller crustaceans, 

 almost too small to see with the unaided eye, swarm in the 

 ponds, forming food for fish and in turn feeding on still 

 smaller animals and plants. 



Many Insects Live in the Water. Many insects are 

 attracted to water, as they lay their eggs in it and the 

 young live either in the mud or water. The larvae of the 

 dragon fly, called nymphs, are mud-colored, strong-legged 

 creatures, which carry a pair of hinged jaws on the front 

 of their heads, which they shoot out to catch their prey. 

 They may often be found on the bottom of a quiet stream 

 and can be brought to the school laboratory. Keep them 

 in a separate jar, for they prey on other living things. 

 Another carnivorous insect is the beetle known as the 

 water boatman. It will even attack small fish. Many 

 other insect larvae live in the mud, such as the young 

 of the water boatman, stone fly, damsel fly, and others. 

 Mosquito larvae or wigglers are often found, either quiet 

 at the surface or wriggling through the water, and the 



