AMERICAN COLEOPTERA. 231 



Size larger (3 mm. or more), eighth joint of antennae evidently longer than 

 wide, terminal joints of both labial and maxillary palpi not distinctly 

 sinuate at tip 26. plaeidiim. 



Size smaller (less than 2 mm.), eighth joint of antennas nearly or quite as 

 wide as long, terminal joints of palpi conspicuously sinuate at tip. 



27. debile. 



14. Elytra evidently a little narrowed from the humeri 15. 



Elytra parallel ... !'• 



15. Size small (1.75 mm.), coarser punctures fine and inconspicuous; elytra rufes- 



cent in apical two-fifths 28. posticum. 



Size larger (usually from 2.5-3.5 mm.), elytra not evidently paler apieally..l6. 



16. Form more gibbous in profile, coarser punctures of pronotum numerous and 



conspicuous; groove of middle tibia rather remote from the margin. 



(Texas) 29. tumiduni. 



Form less gibbous in profile, coarser punctures of pronotum inconspicuous, 

 groove of middle tibia strictly marginal (California ...30. inibiluill. 



17. Metasternum at side nearly equal in length to the first two (visible) ventral 



segments 31. longulum. 



Metasternum at side distinctly shorter than the first two ventrals, usually 

 about one half longer than the first segment 18- 



18. First joint of antennal club unusually narrow slightly more than twice as 



long as wide; coarser punctures very fine and inconspicuous through- 

 out; size larger (4 mm.) 32. iinif'oriiie. 



First joint of antennal club distinctly less than twice as long as wide- • • 19. 



19. Head vaguely longitudinally carinate , 33. iafctigiatuni. 



Head without trace of median carina 20. 



20. Form more elongate, pubescence finer and shorter 21. 



Form more oval, pubescence more conspicuous 22. 



21. Profile slightly gibbous. 



Size larger (2.4-2.7 mm.), form less robust ; grooves of front tibiae parallel 

 and mutually scarcely more distant than from the margins. (Lower 

 California) 34. Otiosum. 



Size smaller (1.6-2.1 mm.), form more robust; grooves of front tibiae more 



widely separated. (Brownsville, Texas) 35. oongruuill. 



Profile not in the least gibbous, the arch flat and symmetrical ; grooves of 

 front tibiae more widely separated 36. vexatum. 



22. Size large, about 4 mm. (southwestern Texas 37. robust urn. 



Size moderate, 2-3.5 mm., coarser punctures of metasternum rather fine and 



sparse (Massachusetts to Louisiana) 38. grave. 



Size smaller, coarser punctures of metasternum strong and numerous. 



(Florida and Texas) 39. porosum. 



Size smaller, body more convex, coarser punctures of metasternum very fine 



and sparse. (Lower California) 40. coiivexnm. 



23. Pubescence exceedingly short, sparse and indistinct 24. 



Pubescence normally developed 25. 



24. Metasternum subequal in length to the second and third ventral segments 



united ; punctuation dual, though rather feebly so in typical speci- 

 mens, but varying in both directions; color castancous (typical) to 



blackish 41. castaneuut. 



TKANS. AM. ENT. SOC. XXXI. JULY, 1905. 



