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CHAPTER V. 



HYMEN"OPTERA— SAW-FLIES, Etc. 



Considered as a division of entomology, perhaps no class of insects is 

 more important than the Hymenoptera. To the student of insect 

 anatomy and physiology they are, as a whole, the most highly 

 differentiated and organised creatures in the insect world. The 

 student of mental phenomena finds in this group instances of rare 

 intelligence and instinctive forethought, often surpassing anything in 

 the animal kingdom ; and the humble but patient observer who 

 studies life-histories will also find abundant scope in this important 

 division. When we remember that this order embraces (besides 

 many others no less distinct in their structure and their habits) 

 saw-flies, gall-flies, ichneumons, ants, bees, and wasps, the truth of 

 the above assertions will be apparent. 



To the student of forest entomology they present a fairly wide field, 

 inasmuch as saw-flies and gall-flies may be considered as injurious 

 insects (though not always to any great extent), and ichneumons, on 

 the other hand, may be considered as beneficial insects. 



To some extent, therefore, in a general way, the student must study 

 the salient features of the whole order, but unfortunately at the 

 present time entomologists are by no means agreed as to classification 

 either as regards the whole order or some of the most important 

 sections. 



As regards the special study of Hymenoptera in its relation to the 

 forest, it may be said that on beating trees and bushes many larvae of 

 several species may be found, and by breeding the same a good 

 representative collection might be obtained. This, however, would 

 be too general for forest entomology, and it is better, therefore, to 

 confine our studies to the more destructive or general species. 



The Hymenoptera have by some been divided into Terebrantia and 



