CHAPTER II 



HYMENOPTERA ACULEATA CONTINUED DIVISION II. DIPLOPTERA 



OK WASPS EUMENIDAE, SOLITARY TRUE WASPS VESPIDAE, 



SOCIAL WASPS MASARIDAE 



Division II. Diploptera Wasps. 



Anterior wings longitudinally plicate in repose; the pronotum 

 extending back, so as to form 

 on each side an angle reposing 

 on the tegula ; the basal seg- 

 ments of the hind body not 

 bearing nodes or scales ; the 

 hind tarsi formed for simple 

 walking. The species either 



solitary or social in their 



, , . , ' ... ,, FIG. 26. Upper aspect of pronotum 



habits; some existing in three and mes onotum of a wasp, Eume- 



forms, males, females, and nes coarctata. a, Angle of prono- 

 tum ; b, tegula ; c, base of wing ; 

 Workers. d, mesonotum. 



THIS division of Hymenoptera includes the true wasps, but not 

 the fossorial wasps. The name applied to it has been suggested 

 by the fact that the front wings become doubled in the long direc- 

 tion when at rest, so as to make them appear narrower than in 

 most other Aculeata (Fig. 27). This character is unimportant 

 in function so far as we know, 1 arid it is not quite constant in 

 the division, since some of the Masaridae do not exhibit it. The 

 character reappears outside the Diploptera in the genus Leucospis 

 a member of the Chalcididae in the parasitic series of Hymen- 

 optera the species of which greatly resemble wasps in coloration. 

 A better character is that furnished by the well-marked angle, 



1 Janet has suggested that the folding is done to keep the delicate hind-margins 

 of the wings from being frayed. 



