300 



METAZOAN PHYLA 



which will not develop fertile seeds unless there are bumblebees in the 

 region to carry the pollen from one flower to another. 



Wasps and hornets may be distinguished from bees by the possession 

 of jaws instead of suctorial probosces, by the body being smooth and not 

 haiiy, and by the legs being never modified for the carrying of pollen. 

 They provision their cells with other animals which they collect and 

 paralyze by stinging before placing them in the cells. Sometimes these 

 cells are provisioned and then sealed, while in other cases the young are 

 fed by the parents as in the case of the bees. An example of the latter 

 are the bald-faced hornets that build paper nests from particles of 

 weathered wood (Fig. 204). The solitary wasps mine in the earth, 



Fig. 204. — Large paper nest, 10 by 8 inches, of the bald-faced hornet, Vespa maculata, 

 made from weathered particles of wood mixed with saliva. There is a legend that man 

 gained the idea of making paper out of wood pulp from observations of these nests. Nest 

 collected in Vermont. 



excavate cavities in wood, or build mud nests. They take no care of 

 their young. The wasps which build the mud nests of many cells, which 

 are familiar in most parts of this country, provision these cells either 

 with the caterpillars of butterflies or moths or with spiders. 



Another insect type which lives in societies and shows specialization 

 and polymorphism is the ant (Fig. 203). There are many species of 

 ants, and they form what has been recognized as a dominant type, 

 dominance being shown in the following ways: (1) by the vast number 

 of individuals which exist; (2) by the variety of structures they display, 

 there being a very large number of species; (3) by their wide distribu- 

 tion, which includes the entire globe; (4) by their longevity; and (5) 

 by their manifold relationships to plants and to other animals. Though 

 the males live only for several months, the lives of the workers may 



