CHAPTER II 



HYMENOPTERA ACULEATA COXTINUED DIVISION II. DIPLOPTEEA 



OK WASPS EUMENIDAE, SOLITARY TRUE WASPS VESPIDAE, 



SOCIAL WASPS MASARIDAE 



Division II. Diploptera — Wasps. 



Anterior icings longitudinally plicate in nyosc ; the inonotum 

 extending hack, so as to form 

 on each side an angle reposing 

 on the tcgala ; the basal seg- 

 ments of the hind hodg not 

 hearing nodes or sccdes ; the 

 hind tarsi fornied for simjjle 

 vxdking. The species either 

 solitary or social in their -' 



7 7 ., ... ■ ,7 Fig. 26. — Upper aspect of pronotum 



hah%ts; some existing m three and mesonotum of a wasp, ^wm-- 



forms, males, females, and "«« coarctata. «, Angle of prono- 



tum ; 6, tegula ; c, base of wing ; 

 WOrlx'evS. ^^ 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 (Tig. 27). This character is unimportant 

 in function so far as we know,^ and 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 Leticos2yis 

 — 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, 



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

 of the wings from being frayed. 



