CHAPTER X. 

 BEES AND WASPS. 



Order HYMENOPTERA. 



The Hymenoptera are in some respects the culmination 

 of the group of insects. They are speciaHzed in several ways 

 but the species are all characterized by ha^'ing the mouth 

 parts developed into both biting and sucking structures. 

 In some respects they seem more specialized than all other 

 orders and in some respects they seem less specialized than 

 the Diptera and Lepidoptera. As a matter of fact in the 

 evolution of the groups of insects there are several orders 

 that must be looked upon as having evolved along divergent 

 lines at the same time and none can be said to really outrank 

 the others. The Coleoptera, Diptera, Lepidoptera, and 

 Hymenoptera, all have a high degree of specialization. It 

 is better not to try to consider them as in the line of a series 

 of steps running up, but as parallel or divergent branches 

 from a general trunk, all of them extending to extreme 

 distances from the primiti^'e stock. 



The Hymenoptera have four wings, and these are pro\'ided 

 with rather few veins and pretty highly specialized in the 

 venation, and in a few groups the veins are practically 

 reduced to nothing. The mandibles are present for the most 

 part in the adult forms l)ut are almost lost in some forms that 

 are fed by the adults in communal forms. They are both 

 mandibulate and haustellate. The larva? are usually footless, 

 fleshy, grub-like animals which depend on their food being 

 sui)plied for them in one way or another and are incapable 

 of moving about and securing their own food supply. This 

 represents a high degree of specialization and reaches its 



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