NORTH AMERICAN COLEOPTERA. 85 



The following table will assist in the determination of the species : 



Prosterniim without trace of lobe in front 2. 



Prosternum lobed, sometimes rather feebly 8. 



2. — Color bright blue ; thorax with a feeble trace of a median sulcus. 



14. Harrisii. 



Color dark bronze or geneous 3. 



3. — Disc of thorax not sulfate at middle, but with an arcuate impression on 



either side 15. dolata. 



Disc of thorax sulcate at middle 4. 



4. — Joints four to eleven of antennae more or less testaceous 16. <leuti|>e!$. 



Antennse uniform, usually entirely metallic 5. 



5. — Joints four to eleven of antennte equally broad in both sexes. 



17. IiKliflcata. 



Antennae gradually more slender to tip 6. 



6. — Posterior tibise of % arcuate 18. seabripeiiui!^. 



Posterior tibise in both sexes straight 7. 



7. — Anterior tibise % abruptly dilated at tip for a short distance without sinua- 

 tion above the dilatation ; last ventral 9 with a narrow but moderately 



deep notch 19. trinervia. 



Anterior tibise % dilated at tip, sinuate above the dilatation ; last ventral 

 of 9 with an extremely feeble truncation, almost entire. 



20. carinipeniiis. 

 Anterior tibiae % abruptly dilated at tip, deeply sinuate above the dilata- 

 tion ; last ventral 9 distinctly emarginate, with a well marked trans- 

 verse ridge in front of the notch 21. canriiia. 



8. — Median sulcus of thorax very well marked, the elevated smoother spaces 



cousiiicuous 9. 



Median sulcus very feeble, linear or almost obliterated, the sides of the disc 



without obvious smoother or elevated spaces 12. 



9. —Anterior tibia % with an abrupt dilatation at tip 10. 



Anterior tibia merely a little broader at tip 11. 



10. — Elytral costae interrupted, but not expanded near the base ; form oblong. 



The first elytral costa very nearly parallel with the suture and elevated 

 nearly to the base ; last ventral without distinct submarginal serrate 



ridge 22. califoriiica. 



First elytral costa sinuous, especially near the apex, evanescent in front of 

 middle ; last ventral with submarginal serrate ridge. 



23. Blanchardi. 

 Elytral costae interrupted, and near the base expanded in broad smooth 

 spaces, more or less confluent ; form broad, depressed. 



24. qua<li*iliiieata. 



11-— Callosities of ventral segments pronounced ; elytral sculpture of rather 

 sharply defined, depressed, punctured spa<',es and narrow, well elevated, 

 smooth ridges 25. exesa. 



12.— Last ventral segment with a distinct, submarginal, feebly serrate ridge, the 



marginal groove consequently deep 26. texaiia. 



Last ventral without submarginal ridge, the marginal groove feeble 13. 



