i8o 



BRITISH ICHNEUMONS. 



\Pezomachus. 



Fifth flagellar joint shorter than 

 broad 7- RUKIPKS, /vVr.?/. 



Basal flagellar joint not shorter than 

 tlie .second. 



Two basal flagellar jomts of equal 

 length. 



Fifth flagellar joint quadrate. 



Abdomen closely punctate through- 

 out. 



Metathoracic costa centrally ob- 

 solete 8. CAVTVS,Forsr 



Metathoracic costa strong through- 

 out. 



Red ; thorax short 9- aemulus, Fors/. 



Black; thorax of normal length ... 10. VULNKRAN.S, /'7/rj-/'. 



Abdomen diffusely punctate. 



Metathorax longitudinally excavate. 



Prothorax and central segments red 1 1. CANALICULATUS, Fors/. 



Prothorax and central segments 

 black 12. PILOSUS, Capron. 



Metathorax not longitudinally ex- 

 cavate. 



Genal costa inflexed ; post-petiole 

 longer than broad 13. acarorum, Limi. 



Genal costa continuous ; post- 

 petiole sub-transverse 14. MANDIBULARIS, Thorns. 



Fifth flagellar joint longer than 

 broad. 



Fifth flagellar joint less than twice 

 longer than broad. 



Abdomen densely punctate and 

 pubescent throughout. 



Thorax comparatively short. 



Metanotum shorter than mesotho- 

 rax ; antennae elongate 15. festinans, Grmi. 



Metanotum and mesothorax of 

 equal length. 



Segments strongly transverse, 

 second and third very short 16. HiERACll, .5r/V/jf. 



Segments not strongly transverse, 

 central normal. 



Petiolar area oblique ; post-petiole 

 longer than broad 17. NIGRITUS, Forsi. 



Petiolar area sub -vertical ; post- 

 petiole transverse 18. SPINULUS, Thorns. 



Thorax not comparatively short. 



Thorax of normal length. 



Metanotum shorter than meso- 

 thorax. 



Meso- double length of meta-notum ; 

 petiolar area large 19. tener, Forst. 



Meso- slightly longer than meta- 

 notum ; petiolar area normal ... 20. MICRURUS, Forst. 



Metanotum and mesothorax of 

 equal length. 



Mesonotum deeply impressed ; basal 

 segment elongate 21. formicarius. Fab. 



Mesonotum not impressed ; basal 

 segment broad 22. Mulleri, /v);-.y/. 



