NATURAL SCIENCES OP PHILADELPHIA. 109 



Basal segment of abdomen vritli apex black ; metathorax with 

 two dilated longitudinal black lines above ; head unusually 



large 49. cephalotes. 



Basal segment of abdomen with two apical yellow spots. 



G9. dissonus. 

 Mesothorax with discal lines entire : 

 Metathorax broadly black at base ; posterior femora at tips and 



within, and apex of their tibioc, black 42. inoratus. 



Metathorax broadly black at base ; posterior femora fulvous, apex 



slightly black, their tibise yellow, black at tips 43. mendicus. 



Metathorax with four black dots on basal middle ; posterior legs 



yellow, with femora black 47. nigrofemoratus. 



Metathorax with three slender black stripes, connected above spines 

 with a broad black band ; posterior femora and tibife with 



black line above 6G. munitus. 



Mesothorax with a curved line, dilated anteriorly, on each side over 



tegul* G7. propinquus. 



Mesothorax with a spot, or a straight line on each side over tegula? : 



Metathorax entirely black, mesothorax opaque 70. minax. 



Metathorax black, with two small spots at base, two elongate ones 

 beneath spines, and a large round one on flanks, all white ; 



mesothorax polished 26. Nestor. 



Metathorax wdth a broad, cruciform black mark above, slightly in- 

 terrupted below the transverse bar ; mesothorax shining. 



34. Tuxtla. 



Metathorax with only tw^o short longitudinal black lines, extending 



from base to spines ; body shining, long, slender, subcylin- 



drical 30. intentus. 



Metathorax with dusky, longitudinal, ill-defined marks above ; 

 scutellum black on middle ; abdomen smooth, and highly 



polished 71 . limattis. 



Mesothorax entirely black : 



Posterior femora and tibice black at ti^js 27. Toros. 



Posterior femora black above, their tibife entirely black ; meta- 

 tliorax with three black stripes, connected above spines by a 



black band 35. solitarius. 



Posterior femora black above, their tibiae entirely black, metathorax 

 black at base above, the sides, apex, and an elongate spot on 



basal middle, whitish 28. famelicus. 



Posterior femora above, and more or less of their tibife above, 

 black ; metathorax with two broad black lines extending from 

 base to spines, and a narrow, central, black line at apex. 



29. tenebricus. 

 Posterior femora and tibioe fulvous, the former slightly dusky 

 above ; metathorax with two broad stripes from base to spines, 

 and a bilobed mark at apex ; abdomen short and polished. 



31. gracileutus. 



