180 THE ENTOMOLOGIST. 



all the males and females which will work in together, and then 

 goes on with those males which will not so accommodate them- 

 selves, ending with both sexes of Ascogaster, as forming a distinct 

 division of the same genus, from which the central nervure 

 bisecting the cubital cell forms a much better character than is 

 often obtainable for superficially very distinct genera, e. g. 

 Ascogaster and Sigalpkus. 



Chelonus, Jur. 

 (32) 1. Tegulae infuscate or black. 



(19) 2. Antennae of female more than 16- jointed ; male 



anus entire. 



(4) 3. Abdomen mainly red . . . 1. westmceli, Curt. 

 (3) 4. Abdomen black or only basally pale. 



(16) 5. Kadius apically arcuate, and, in lower wing, 



centrally curved. 



(11) 6. Hind tibiae basally, and base of their tarsi, red ; 



length, 5-6 mm. 

 (10) 7. Parastigma infuscate ; frontal impression rugu- 

 lose. 



(9) 8. Antennae centrally dilated and apically con- 

 stricted . . . . .2. inanitus, Linn. 



(8) 9. Antennae setiform throughout . . 3. submuticus, Wesm. 



(7) 10. Parastigma testaceous ; frontal impression niti- 



dulous . . . . . .4. speculator, Msh. 



(6) 11. Hind tibiae basally, and their tarsi entirely, 

 black; length, 3-4 mm. 



(13) 12. Frontal impression rugose and not carinate 



5. corvulus, Marsh. 



(12) 13. Frontal impression nitidulous and centrally 



carinate. 

 (15) 14. Abdomen immaculate; hind tibiae broadly red 



centrally ..... 6. carbonator, Msh. 



(14) 15. Abdomen basally fiavous ; tibiae narrowly red 



centrally . . . . . .7. decoras, Marsh. 



(5) 16. Radius straight, and, in lower wing, basally 



curved and nearly straight centrally. 

 (18) 17. Antennae 32-jointed, longer than body ; size, 



3 mm. . . . . . .8. catulus, Marsh. 



(17) 18. Antennae 23- jointed, not longer than body ; 



size, 2^ mm. . . . . .9. pusio, Marsh. 



(2) 19. Antennae of female 16-jointed ; male anus api- 

 cally cleft. 

 (21) 20. Anal cleft nine times longer than broad 



10. risorius, Reinh. 



(20) 21. Anal cleft at most thrice longer than broad. 

 (31) 22. Abdomen black ; size at least 2 mm. 



(26) 23. Head cubical and cheeks buccate. 



(25) 24. Prothorax elongate ; antennae 25-jointed 



11. secutor, Marsh. 

 (24) 25. Prothorax normal ; antennae of male 23-jointed 



12. exilis, Marsh. 



