INSECT ORDERS 261 



the females sting but, since the sexes cannot readily be distinguished, it 

 is a good idea to show due respect for all of them. They are subdivided 

 as follows : 



a. True wasps. These include forms like the red wasps, yellow jack- 

 ets, and hornets. They make nests by chewing up bits of worn 

 wood and spreading them out in the form of a paste to dry, thus 

 duplicating our wood pulp process for making paper. 



Photo by Winchester 



Fig. 17.16. Nest of the mud dauber. This thread-waisted wasp builds its brood 



chambers of mud, then stings a spider to paralyze it and puts it in a chamber with an 



egg to furnish fresh food for the larva when it hatches. 



b. Thread-waisted wasps. Characterized by an extremely thin con- 

 nection between the abdomen and thorax which looks little larger 

 than a thread. These include such interesting forms as the mud- 

 daubers that build nests of mud containing several individual cells. 

 After laying an egg in each cell the female will find and sting 

 spiders in their thoracic ganglia so that they are paralyzed but not 

 killed. She will put one or more of these in each cell and seal it up 

 with mud. When the larvae hatch out they find fresh juicy spiders 

 to feed on during their larval development. 



c. Digger wasps. These dig holes in the ground and put paralyzed 

 spiders or caterpillars in with the eggs. Some do not have wings 

 and are called velvet ants. 



4. Boring hymenoptera. In this group the females are adapted for 

 boring holes in plants or animals to deposit their eggs. Those deposited 

 in plants cause the plant to produce a gall at the spot and the larvae de- 

 velop in this gall. Others deposit the eggs in the bodies of such animals 

 as spiders or caterpillars and the larvae live as parasites in the body of 

 the host. 



