Illustrated Studies 



89 



Fig. 159. — 

 Ichneumon fly 



Compare the cells of 

 bumble bee (Fig. 153) with 

 those of hive bee. They 

 differ not only in shape but 

 in material, being made of 

 web instead of wax, and 

 they usually contain larvae 

 instead of honey. Only a 

 few of the queens among 

 bumble bees and wasps 

 survive the winter. How 

 do ants and honey bees 

 provide for the workers 

 also to survive the win- 

 ter? Name all the social 

 insects that you can think of. Do 

 they all belong to the same order? 



The ichneumon fly shown enlarged in 

 Fig. 159 lays its eggs under a caterpillar's 

 skin. What becomes of the eggs ? The 

 true size of the insect is shown by the 

 cross lines at a. The eggs are almost 

 microscopic in size. The pupas shown 

 (true size) on caterpillar are sometimes 

 mistaken for eggs. The same mistake is 

 made about the pupa cases of ants. 

 Ichneumon flies also use tree-borers as 

 "hosts" for their eggs and larva. Is 

 this insect a friend of man ? 



The digging wasp (Figs. 160 and 161) 

 supplies its larva with caterpillars and 

 closes the hole, sometimes using a stone 

 as pounding tool. Among the few 

 other uses of tools among lower 

 animals are the elephant's use 

 of a branch for a fly brush, and 

 the ape's use of a walking stick. 

 This wasp digs with fore feet 

 like a dog and kicks the dirt 

 out of the way with its hind 

 feet. 



Are the wings of bees and 

 wasps more closely or less 

 closely veined than the wings 

 of dragon flies? (Fig. 177-) 



FIG. 161. — Wasp using pebble. 



From Peckham's," Solitary Wasps," 

 Houghton, Mifflin & Co. 



