46 



NATURAL HISTORY 



Bruinu II 



Ichneumon fly {Ophion macnirum) 

 laying eggs in the cocoon of a Cecropia 

 moth. 



plants which will become food for the larvae or caterpillars. Others 

 lay their eggs either in the ground where they are protected, or in 



dead bodies of animals on which 

 the larvae may feed, as in the case 

 of certain beetles, or in a ball of 

 dung, as in the case of the dung 

 beetle. Certain ichneumon flies 

 bore deep into tree trunks in order 

 to lay their eggs in the larvae of 

 wood-boring insects. Some w^asps 

 paralyze caterpillars or spiders, 

 laying eggs in the still living victim 

 so that when the eggs hatch the 

 young larvae will have food. In 

 many animals, food is provided in 

 the yolk of the egg, the eggs of 

 fish and birds being examples. 

 Spiders and earthworms form 

 cocoons, which in the case of the 

 earthworm are usually filled with a nutritive fluid on which the young 

 feed after they are hatched, while in the cocoon of the spider the 

 young feed upon each other, the strongest of the group surviving. 



Care of Eggs by Parents 



Some of us as youngsters have angled for sunfish and will always 

 remember the thrill that came when a brightly colored male dashed 

 at the bait dangled over the hollowed nest containing eggs which he 

 was guarding. From the simple nest of sunfish and salmon through 

 the more complicated nests of the stickleback or lake catfish we come 

 to the more elaborate nesting habits of birds. Some birds, as terns, 

 sandpipers, or gulls, simply make shallow holes in the sand, as does 

 the sand ostrich. Grebes and rails make nests of floating decaying 

 vegetation. Nuthatches and woodpeckers make nests in holes in 

 trees where the young are protected. At the top of the ladder are 

 more elaborate nests such as those of the oriole and oven-bird of our 

 latitude or the tailor bird and weaver bird of the tropics. 



Care of Young 



Sir Arthur Newsholme has said that the most dangerous work in 

 the world is that of being a baby. If the young of plants and ani- 



