OF WASHINGTON, VOLUME XIII, 1911. 215 



A CLASSIFICATION OF THE SUBORDER CHALASTOGASTRA 



OF THE HYMENOPTERA. 



BY S. A. ROHWER. 



That the morphological characters exhibited by the most 

 useful organs were least important as exhibiting relationship, 

 for the reason that such characters were most subject to varia- 

 tion, ivhereas structures of less use and importance -were neces- 

 sarily less subject to variation and hence more indicative of 

 affinities. (Dr. T. N. Gill, 1901.) 



The name "Chalastogastra" is used, as the best one that 

 has been proposed, and it has been in use for a number of years 

 in Euiope. Many other names have been given to this group 

 of insects, but most of them are based on their habits. 



The nomenclature of the thorax and anterior wing is that 

 given by Snodgrass. 1 The nomenclature of the posterior 

 wing is that used by Cresson. The first dorsal abdominal 

 segment (basal plates of authors) is called the propodeum. 



The present paper does not deal with groups lower than 

 tribes. Genera not known from specimens are not placed. 

 All species known to the writer can easily be placed in the 

 tribe to which they belong. It would be a great favor to the 

 writer if other workers would place the genera, not placed and 

 known to them, into the division to which they belong. 



/ 



Suborder CHALASTOGASTRA. 



TABLE TO THE SUPERPAMILIES. 



Posterior margin of the pronotum straight or nearly so, being 

 nearly the shortest distance between the anterior 

 margins of the tegulae; mesonotum very short and 

 never extending much beyond the anterior margins 

 of the tegulaa; proepimeron wanting Megalodontoidea 



Posterior margin of the pronotum strongly curved; mesonotum 

 longer and extending well beyond the anterior margins 



of the tegulae I 



1. Metanotum concealed, but the metapostnotum is present 

 and large; antennae inserted much below the lower 

 margins of the eyes, and below the apparent clypeus; 

 propodeum not divided; proepimeron wanting; an- 

 terior wings with two cubital cells Oryssoidea 



Metanotum always present, although the metapostnotum 

 is sometimes concealed; antennae inserted well above 

 the clypeus; anterior wings with more than two 



cubital cells 2 



1 The thorax of the Hymenoptera. Proc. U. S. Nat. Mus., vol. 39, 

 no. 1774, pp. :!7-91, plates 1-16. 1910. 



