Mar. 1S99.] Fall; On American Species of AcM^obtRA. 19 



Thorax with lateral margin yellow in more than basal half 8 



Thorax unicolorous or with only a small lateral yellow spot behind the middle I 



1. Last ventral with thick subapical crest which is subangulate at middle 6 



Last ventral without apical crest (except rarely in connexa) 3 



Last ventral with thin apical plate which is not subangulate at middle (sometimes 



feebly developed or nearly obsolete in acuta and labyrinthica') 2 



2. Thoracic margin narrow, not reflexed, not or scarcely visible posteriorly from 



above. 



Surface bronzed without spots morbosa. 



Surface bluish, elytra with scattered small yellow spots ornata. 



Surface bronzed, elytra with yellow markings. 



Markings more constant, a lateral transverse spot at the middle of the elytra 



being most conspicuous ; form depressed. . , flavosticta. ' 



Markings more intricate and very variable. 



Form narrower, less depressed, punctures of elytral stride finer, .acuta. 

 Form broad, depressed, punctures of elytral stride coarser. 



labyrinthica. 



Form depressed, strongly narrowed posteriorly CUneata. 



Thoracic margin slightly reflexed, visible throughout from above ; elytra with nu- 

 merous .small yellow spots, often intricately joined, sides at tip red.rubronotSita. 



3. Thorax widest at base, form rather narrow, less flattened 5 



Thorax more or less distinctly widest a little in front of the base, and usually 



slightly wider than the elytra ; form broader and more flattened 4 



Thorax widest at middle 7 



4. Elytra with yellow markings on the disk. 



Form more slender and more gradually narrowed behind ; thorax without lateral 

 spot, yellow markings of the elytra irregularly longitudinally joined toward the 



base connexa. 



Form less slender, more parallel, and less gradually narrowed behind ; elytra 

 with three more or less irregular transverse bands not reaching the suture, and 



an apical spot variegata. 



Elytra with a few (mostly lateral) small orange red spots which show a tendency to 



coalesce transversely . . van dylcei. 



Elytra with three or four lateral yellow spots, that at the middle being largest. 



prorsa. 

 r. Bronzed, sides of thorax more strongly rounded, elytra with three reddish spots at 



the sides behind the middle, the middle one extending inward dohrni. 



Blue, sides of thorax less rounded, elytra with same markings mariposa. 



6. Piceous, faintly bronzed, elytra with a few inconspicuous yellow spots toward the 



sides dolorosa . 



Cupreous, elytra each with two apical marginal red spots postica. 



7. Sides of elytra entirely yellow, inner margin strongly indented, no discal mark- 



ings liorni. 



8. Outer interval of elytra acutely tuberculate behind the middle daggettl. 



Outer interval of elytra not tuberculate 



Thoracic margin reflexed, plainly visible throughout from above, .decipiens. -^^ 

 Thoracic margin narrow, not reflexed fcCalaris. 



