ENTOMOLOGY IN OUTLINE HYMENOPTER A 109 



The three divisions of the body are well denned. The head is, in 

 many species, movable on the thorax, while the thorax is sharply 

 divided from the abdomen, in some cases, as in the wasps, being joined 

 by a mere thread-like process. 



The metamorphosis of the Hymenoptera is complete. The eggs are 

 not remarkable for either form or color, and are usually somewhat 

 oblong. They are laid in various positions, according to species, in 

 some cases being deposited in the bottom of cells prepared to receive 

 them; in others, as in the parasitic species, being attached to or placed 

 in the body of their victims. In all, except the two lower families, the 

 larvae are maggot-like creatures, footless, and incapable of extended 

 motion, and, in many cases, wholly dependent for their existence upon 

 the care of the adults. 



This order is divided into two suborders, the Terebrantia and the 

 Aculeata. The former comprises a number of parasitic insects, as the 

 ichneumons, braconids, chalcids, etc.; the gall-flies, saw-flies, etc.; while 

 the latter includes the stinging forms, as bees, wasps, and ants. 



Suborder TEREBRANTIA. 



In the modern system of classification it has become the rule to com- 

 mence with the lower forms and work upward to the higher, and, for 

 this reason, the Hymenoptera, being recognized as the highest devel- 

 oped of any of the members of the insect world, is placed at the top of 

 the list. In this arrangement the various orders and families may be 

 compared to a pyramid, in which the less specialized, lower, and baser 

 kinds form the foundation, and in which there is a constant ascent 

 until the capstone is reached, and, in this case, this is the higher order 

 of Hymenoptera. So, in accordance with this plan, the suborder 

 Terebrantia, which is the less specialized of the two suborders, and 

 contains the lower forms of the order, takes its place first in our con- 

 sideration, and in this the lower families are first noticed. 



Comstock gives us the following synopsis of the suborder Terebrantia : 



THE BopiNG HYMENOPTERA. Suborder Terebrantia. 



The Plant-eating Hymenoptera. 



The Saw-flies. Family Tenthredinidae. 



The Horn-tails. Family Siricidae. 

 The Gall-inhabiting Hymenoptera. 



The Gall-flies. Family Cynipidse. 

 The Parasitic Hymenoptera. 



The Trigonalids. Family Trigonalidae. 



The Ichneumon-flies. Family Ichneumonidae. 



The Stephanids. Family Stephanidae. 



The Braconids. Family Braconidse. 



The Ensign-flies. Family Evaniidaa. 



The Chalcid-flies. Family Chalcididae. 



The Proctotrupids. Family Proctotrupidaa. 



