1895.] NATURAL- SCIENCES OF PHILADELPHIA. 521 



3. Submedian cell of posterior wings terminating before the 



origin of the cubital vein 4 



Submedian cell of posterior wings not terminating before the 



origin of the cubital vein 8 



4. Second ventral segment prominently angular 6 



Second ventral segment not angular 5 



•5. First abdominal segment subpetiolate, apical margins of the 

 segments broadly margined with pale pubescence; antennae 



short eximiu8. 



First abdominal segment sessile, the abdomen red in part, not 

 pubescent; antenna? long, slender pietifrons. 



6. Middle segment coarsely rugose throughout 7 



Middle segment not rugose, the furrow forming the enclosure 



wide, crossed longitudinally by strong ridges; antenna* 

 shorter than head and thorax, joints 2-6 of fiagellum 

 strongly rounded-out beneath nigrifrons. 



7. Antenna? very long; palpi obscure mystaceus. 



Antenna? shorter; palpi in part yellow campestris.* 



8. Middle segment more or less coarsely sculptured 9 



Middle segment not coarsely sculptured, smooth 31 



9. Dorsulum strongly punctured 10 



Dorsulum not strongly punctured 20 



10. First abdominal segment subpetiolate; last ventral segment 



bifid 19 



First abdominal segment not subpetiolate 11 



11. Fifth ventral abdominal segment armed with a strong promi- 



nence at each side. (See fig. 1.) con/ertus. 



Fifth ventral segment unarmed 12 



12. Mesosternum dentate laterally (entirely red, with pale mark- 



ings) 13 



Mesosternum not dentate 14 



13. Middle segment not at all yellow; abdominal fascia* nar- 



row; fuscous cloud of fore wings not extending beyond the 

 apex of marginal and third submarginal cells . . . . denlatus. 

 Middle segment yellow in greater part; abdominal fascia un- 

 usually broad; fuscous cloud of fore wings extending to 

 apex of wing diversus. 



14. Eighth and ninth joints of fiagellum spinose beneath .... 16 

 Eighth and ninth joints of fiagellum not spinose, at the most 



tuberculate 15 



15. Enclosed space on middle segment smooth ; middle segment 



and first and last abdominal segments more or less red; 



legs entirely red tricolor. 



Enclosed space on middle segment distinctly striated; middle 



*See foot note, p. 518. 



