BRITISH ICHNEUMONS. 235 



TRIBE. 



PHAEOGENIDES. 



The species of tliis tribe were grouped together by Wesmael, in his 

 "Tentamen" (1844) under the name oi Ichneumones-pneustici, which was 

 retained by Hohngren, in 1889, and Thomson, in 1891 ; but in 1896 

 Eerthoumieu apphed that of Cyclopneusiici to it, in contradistinction from 

 the Stenopneusiici, which latter term embraced all those genera already 

 described. Ash mead more recently split off the sub-tribe Heresiarchini 

 from, and raised it to equal dignity with, the Phaeogenides, reinstating the 

 Alomyides nearly in the position here assigned to it. 



Tabic of Siib-iribcs. 



(2). I. Mandibles apically acute, lower tooth wanting" ; 



head broad Heresiarchini. 



(i). 2. Mandibles apically obtuse, bidentate ; head normal Phaeogenini. 



Sub-tribe. 

 HERESIARCHINI. 



The apically acute and edentate mandibles, very broad head, and 

 usually strongly concave occiput will at once distinguish the present sub- 

 tribe from the next, with which alone it can be confused by reason of the 

 circular metathoracic spiracles and general conformation. Only four 

 genera are enumerated as known to science, of which but one has, some- 

 what recently, been found to occur in Britain. This genus differs from the 

 more typical ones in having the vertex of the head entire. 



As to the validity of this sub-tribe, no inconsiderable doubt may be 

 entertained, since, as will be found in the Phaeogenini, the mandibular 

 dentation is prone to wide and varied modification, becoming, in the genus 

 Ischnus, very nearly unidentate by reason of the pusillity of the lower 

 tooth ; in the latter genus, however, the scutellum is sub-conical. There 

 can, I think, be no doubt that this sub-tribe is too nearly related with the 

 remainder of the Phaeogenides to merit equal rank therewith. 



STENODONTUS, Eerthoumieu. 



Berth. Ann. Soc. Yx. 1896, p. 346 ; Gnathoxys, Wesm. Nouv. Mem. Ac. Brux. 1S44, 

 pp. 165, 168 {«(?^ VVestw.). 



Head buccate, broader than thorax, very finely punctate ; mandibles 

 apically acute, with the lower tooth entirely wanting ; clypeus broader than 

 long, somewhat convex, hardly discreted from the centrally protuberant 

 face, its apex simple and mutic ; genal costa sub-continuous and not ele- 

 vated. Antennae filiform, pubescent, somewhat incrassate ; scape hardly 

 emarginate and longer than post-annellus ; second flagellar joint quadrate, 

 the following transverse. Thorax deplanate ; pronotum nitidulous ; meta- 

 notum finely areated, not produced posteriorly. vScutellum not strongly 

 elevated. Abdomen shining, elongate ; post-petiole quite smooth, some- 

 what narrow, and laterally immarginate ; thyridii distinct and far from base 

 of second segment ; terebra stout. 



