6 10 THE STUDY OF INSECTS. 



EE. Wings folded in plaits when at rest.* p. 657. 



Vespina. 



DD. First segment of the posterior tarsi enlarged, flattened, 



and more or less clothed with hair ; hairs clothing thorax 



plumose (Fig. 737, c). p. 664 Apina. 



Suborder TEREBRANTIA (Ter-e-bran'ti-a). 

 The Boring Hymenoptera. 



The Hymenoptera are divided into two suborders, the 

 Boring Hymenoptera and the Stinging Hymenoptera. In 

 the first of these suborders the caudal end of the abdomen 

 of the female is furnished with an organ, the ovipositor,, 

 which is fitted for boring a hole into which an egg is to be 

 placed, and also for conveying the egg into this hole. The 

 form of the ovipositor varies greatly in the different families ; 

 in one the boring parts are represented by a pair of saws, by 

 means of which slits are made in the leaves of plants and an 

 egg conveyed into each slit ; in other families this organ is 

 truly a boring instrument by means of which deep holes are 

 made into trees and eggs placed in these holes ; and in still 

 other cases the organ is fitted for thrusting an egg into the 

 body of another insect. 



Although the ovipositor is very conspicuous in many 

 members of this suborder, there are others in which it is 

 more or less completely concealed within the body, and thus 

 affords but little aid to the student who is classifying his 

 specimens ; moreover, in the case of male insects we must 

 always depend on some other character. Fortunately there 

 is another character by which the suborders can be separated. 

 In the Boring Hymenoptera the trochanter of the hind leg" 



* It is sometimes difficult, especially in the case of cabinet specimens 

 with the wings spread, to determine whether a species is one that folds its 

 wings or not. But we know of no other character which will always distin- 

 guish the Vespina from the Sphecina. The following will often be of ser- 

 vice: In all North American Vespina veins V 2 and V 8 both arise from the 

 second submarginal cell; in many of the Sphecina they do not. 



