CHAPTEE XXII 



HYMENOPTEEA HYIIENOPTEEA SESSILIVENTEES CEPHIDAE 



OEYSSIDAE — -SIEICIDAE TENTHEEDINIDAE OE SAWFLIES 



Order IV. Hymenoptera. 



Wings four, membranous, without scales, usually transparent, never 

 very large, the posterior pair smaller than the anterior ; the 

 cells formed hy the nervures irregular in size and form, never 

 very numerous (less than tiventy on the front, than fifteen on 

 the hind, luing). Mandibles conspicuous even ivhen the other 

 parts of the mouth form a, piroboscis. The side-pieces of the 

 prothorax are disconnected from the pronottim and overlap 

 the prosternum, usucdly entirely concealing it. The femcdes 

 are furnished at the extremity of the body vnth either saw, 

 sting, or ovipositor ; these parts may either be ivithdraivn 

 into the body or be permanently protruded. The metamor- 

 phosis is great and abrupt, the chief changes being revealed 

 in the pupa disclosed at the last moult of the larva ; this moult 

 is frequently delayed till long after growth has been com- 

 pleted. In the pupa the parts of the perfect Insect are seen 

 nearly free, each covered in a very delicate skin. 



The term Hymenoptera includes ants, bees, wasps, sawflies, and 

 the tribes of innumerable Ichneumon-flies. The Order is of 

 enormous extent, consisting even at present of tens of thousands 

 of described and named species, and yet these are but few in 

 comparison with those that remain unknown. It has good claims 

 to be considered the " highest " Order of Insects. Sir John 

 Lubbock says : " If we judge animals by their intelligence as 

 evinced in their actions, it is not the gorilla and the chimpanzee, 

 but the bee, and above all the ant, which approach nearest to 



