CARE OF EGGS 



307 



parent. On the other hand, the great majority of egg- 

 laying or oviparous species insure the developing young 

 against the attacks of enemies by providing them with 

 some means of protection. The crabs, for example, attach 

 the eggs to appendages of the body and fight off invaders, 

 the spiders often carry their ova in silken cases, many 

 animals construct brood pouches, and there are thousands 

 of species that hide their eggs in safe retreats. Among 

 many of the bees, wasps, and certain beetles not only 

 are the eggs hidden but also a supply of food' is placed 

 within easy reach. 

 Many of the fishes, such as salmon and trout, bury the 



Fig. 74. — The Metamorphosis of the Monarch Butterfly. 



eggs in the sand, others like the stickleback construct 

 elaborate nests for them, the sea horses and related pipe 

 fishes retain the eggs and young in folds of skin under- 

 neath the body, while certain other fishes attach their 

 offspring to the skin or even carry them in the mouth. 

 The eggs of frogs and toads are usually laid in water, 

 though a few dry country species conceal them in folds 

 of the skin on the back. The eggs of birds are usually 

 placed in nests and the heat required for development is 

 provided by the brooding parent. In the mammals, or 



