HYMENOPTERA 



CHAP. 



formed by the pronotum on the dorsal part (Fig. 26). By a 

 glance at this part a Diplopterous Insect can always be readily 

 distinguished. 



Three families are at present distinguished in the Diploptera, 

 viz. Eumeiiidae, Vespidae and Masaridae. We anticipate that 

 Eumenidae and Vespidae will ultimately be found to constitute 

 but one family. 



Fam. 1. Eumenidae Solitary True Wasps. 



Claws of the feet toothed or bifid ; middle tibiae with only one 

 spur at tip. Social assemblages are not formed, and there is 

 no worker-caste, the duties of nest-construction, etc., 'being 

 performed solely l>y the female. 



The Eumenidae, or solitary wasps, are very little noticed by 

 the ordinary observer, but they are nevertheless more numerous 



than the social Vespidae, about 800 

 species being known. In Britain we 

 have sixteen species of the solitary, as 

 against seven of the social wasps. 

 The Eumenidae exhibit a considerable 

 diversity in form and structure ; some 

 of them have the pedicel at the base 

 of the abdomen very elongate, while 

 in others this is so short as to be 

 imperceptible in the ordinary position 

 of the body. A repetition of similar 

 differences of form occurs in the social 

 wasps, so that notwithstanding the 



FIG. 27. Emnenes flavoaicta 9 . , . i i -.L j.i i 



Burma. The wings on the left difference in habits there seems to be 

 in the position of repose, to no satisfactory way of distinguishing 



the members of the two families ex- 

 cept by the structure of the claws and tibial spurs. 



Fabre has sketched the habits of a species of Eumenes, 

 probably E. pomiformis. This Eumenes constructs with clay a 

 small vase-like earthenware vessel, in the walls of which small 

 stones are embedded (like Fig. 28, B). This it fills with food 

 for the young. The food consists of caterpillars to the number 

 of fourteen or sixteen for each nest. These caterpillars are 

 believed to be stung by the parent-wasp (as is the case in the 



