ART. 16 WASPS OF THE SUBFAMILY BKACONINAE MUESEBECK 23 



Up to the present Agathis Latreille has been held distinct from 

 {Microdvs Nees) =Bass}is Fabricius solely on the basis of the length 

 of the face, and on this character it has usually been more closely 

 associated with (Cremnops Foerster) =Bracon Fabricius, being even 

 treated as a subgenus of Bracon by Viereck.'^ Although Lyle'^ con- 

 sidered Agathis to be separable from Bassus "by characters that are 

 of httle more than specific value," he nevertheless held the two dis- 

 tinct, evidently believing the difference in the length of the face to 

 be rather clear-cut. The study of a large amount of material, how- 

 ever, has convinced me that it is virtually impossible to separate 

 species on this character alone; and although I dislike to suppress a 

 name so long and generally employed, I can find no basis upon which 

 to adequately distinguish Agathis from Bassiis and beheve it advis- 

 able to sjTionymize the two genera. 



Wcsmael proposed the name Therophilus for a subgenus of Microdus, 

 which accounts for the inclusion of this name in the synonymy of 

 Bassus. Aerophilopsis Viereck was likewise published as merely the 

 name of a subgenus of Bassus; and Viereck himself has recently^* 

 explained that his Lytopylus is not the Lytopylus of Foerster, but is 

 rather a synonym of his own subgenus Aerophilopsis. 



The following characters apply to Bassus, as I have considered the 

 genus in this paper: Head transverse; face varying from long and 

 rostriform to very short; maxillary palpi normal, five-segmented, not 

 modified to form a long beak; labial palpi four-segmented, the third 

 segment often very short and sometimes hardly distinct ; frons usually 

 immargined, but in a few species the frontal impressions are distinctly 

 carinately margined ; parapsidal furrows nearly always impressed or 

 indicated, rarely entirely wanting; mesopleural furrow varying from 

 strongly impressed and coarsely foveate to very weak and completely 

 smooth; sculpture of propodeum variable; first cubital and first dis- 

 coidal cells confluent; second cubital cell usually very small, triangu- 

 lar, never broadly sessile, the second abscissa of radius rarely present 

 and then very short; length of submediellan cell variable, the first 

 abscissa of mediella varying from much shorter to distinctly longer 

 than the second; legs moderate; inner spur of posterior tibia rarely 

 quite half as long ?.s the basitarsus; posterior basitarsus not incras- 

 sate; tarsal claws not cleft, but with a basal tooth which is usually 

 broad and pronounced; abdomen sessile, the basal tergites sometimes 

 more or less sculptured, the first often with one or two conspicuous 

 dorsal longitudinal keels; ovipositor prominently exserted, the sheaths 

 at least as long as the abdomen. 



12 Bull. 22, Conn. Geol. and Nat. Hist. Survey, 1917 (1916), p. 231. 



13 The Entomologist, vol. 53, 1920, p. 177. 



" Proe. U. S. Nat. Mas., vol. 69, 1921, p. 139. 



