ORDER HYMENOPTERA : ANTS, BEES, WASPS, ETC. 221 



are sterile females) of some of the social forms wings are 

 absent, but males are rarely wingless. On either side of 

 the mesonotum above the roots of the front wings there is 

 articulated a plate, known as the tegiila, the size and form of 

 which is of some importance in classification. 



The abdomen is either broadly connected with the 

 thorax, in the common fashion, when it is said to be 

 " sessile," or it is contracted anteriorly to a slender " waist," 

 when it is spoken of as stalked or " petiolated." 



The eggs are deposited either (i) in the tissues of plants, 

 or (2) in or on the eggs or larvae of other insects, or (3) in 

 special "cells" or chambers constructed by the parent (or 

 foster-parent in the case of most social Hymenoptera) ; in 

 the last case provision for the ensuing larva may be enclosed 

 in the same chamber with the egg, or the egg and its issue 

 may be the object of sustained solicitude to the parent (or 

 foster-parents). 



The larva may be caterpillar-like, with thoracic legs and 

 abdominal pseudopods ; but more commonly it is legless and 

 maggot-like, though with the head larger and more distinct 

 than it is in the Dipterous maggot. The larva (i) may feed 

 on plants, or (2) may be a parasite in the tissues of plants, in 

 which case it sometimes forms galls, or (3) may be parasitic 

 in the egg or larva or pupa of another insect, or (4) may be 

 provided for by the parent in various ways that simulate 

 conscious forethought. 



The pupa may be enclosed in a cocoon, or not ; its wings 

 and appendages are not bound down by chitinous exudation 

 as in the obtected pupa of certain other insects. When the 

 larva has lived in a special chamber or " cell," constructed by 

 the parent or foster-parent (worker), the pupa continues to 

 occupy the chamber, in which it may either spin a cocoon 

 or not. 



Parthenogenesis is very common in this order ; and 

 among some gall - flies {Cynipidce) a. parthenogenetic 

 generation regularly alternates with a sexually produced 

 generation. 



A good many of the stinging Hymenoptera live in 

 communities. The organisation of these communities 

 varies considerably, but a typical community consists of (i) 



