HYMENOPTERA. 245 



indirect mode of development, some larvae being foot- 

 less, and so completely helpless that they are fed by 

 their parents. 



According to the standards we have adopted, the 

 most specialized insects in other orders have been 

 those in which the mouth parts have been fitted for 

 one office, that of sucking fluids (Hemiptera, Lepi- 

 doptera) ; or else in large part suppressed, the work 

 of the insects being narrowed down to the perpetua- 

 tion of its species (Ephemeridae): in fact, any sort of 

 a modification of the parts of the body, either result- 

 ing from extra development or suppression, which has 

 removed the adult more widely from its own young or 

 its supposed Thysanuran ancestor, or from both of 

 these forms, and narrowed its field of work, has been 

 deemed a sure index of extreme specialization. 



In the Hymenoptera the complexity of the mouth 

 parts fitted to do so many different kinds of work is 

 not, therefore, a mark of the highest specialization. 

 The tendency to gather into communities is found in 

 groups of other orders (white ants) having similar 

 habits, and the effects upon structures are not so fun- 

 damental that we are thrown into any doubts with 

 regard to the order to which any of the social insects 

 belong. The indirect mode of development is evi- 

 dently a characteristic shared in common with several 

 other allied orders, and occurs as well in smaller groups 

 of the first series of orders, wherever habits make 

 this method necessary or useful. Friederich Brauer, 

 although considering them the '' highest " of insects, 

 points out that, notwithstanding the " higher " mode 

 of development, the Hymenoptera remind one more 



