136 E. T. CRESSON. 



Section I. — Abdomen black or bh'.e, without pale bands or spots, except sometimes on 



apex of first or last segments. 

 Posterior legs entirely black. 

 Antennse orange-yellow, black at extreme base and apex... 12. flavicornis. 

 Antennae black, with pale annulus. 

 Apex of abdomen immaculate. 

 Wings dark fuliginous. 

 Postpetiole entirely black. 



Face entirely black; annulus on antennse broad 8. galenus. 



Face black; white laterally; annulus on antennae narrow. 

 Scutellum black. 



Antennfe short, pale annulus entire 9. torviilUi^. 



Antennse long, pale annulus interrupted beneath. ..10. eitiinus. 



Scutellum white; sides of face broadly white 28. hii^triC'US. 



Postpetiole more or loss white at tip; face white, sometimes black in 



lateral depressions 56. unifa!!iciatorius. 



Wings hyaline or subhyaline. 



Small; face entirely black or with pale orbital lines 21. acerbus. 



Larger; face entirely white or spotted with white. ..14. ^K^riptitroilS. 

 Apex of abdomen with one or more pale spots. 

 Postpetiole entirely black. 



Posterior trochanters black 40. breviciiictor. 



Posterior trochanters white 41. extreniatatis. 



Postpetiole narrowly margined at apex with white. 



Metathorax immaculate 32. citatus. 



Metathorax with round white spot on each flank 33. merus. 



Antennse entirely black or blue. 

 Scutellum entirely black or blue. 



Body deep black, rather shining; wings hyaline 17. odiostlS. 



Body blue-black, opaque; wings dusky Ambly. montanus. 



Scutellum white. 



Face white with black central stripe. 



All the coxse black 35. neutralis. 



Four anterior coxse white 30. pepticus. 



Face entirely white i 31. per%'agUS. 



Posterior legs black, their tibise more or less white. 

 Antenna black, with pale annulus. 

 Apex of abdomen immaculate. 

 Postpetiole entirely black. 

 Posterior tibise white, black at tips; four anterior coxse and trochanters 



white 48. vagans. 



Posterior tibise with an entire white annulus at base. 



Posterior trochanters white, tibise white at base; scutellum white 



laterally 25. iiavus. 



Posterior trochanters black, tibise black at extreme base; scutellum 



entirely white 47. prouiptus. 



Posterior tibise witii white line above towards base. 



Metathorax immaculate; annulus on antennse entire 46. sagns. 



Metathorax with two white spots behind; annulus on antennse in- 

 terrupted beneath 53. Hublittus, var. 



