HENRY J. FRANKLIN. 83 



38. The second and third dorsal abdominal segments distinctly red- 



dish-ferruginous laticinc'tiis. 



The second and third dorsal segments not reddish-ferruginous. .39. 



39. Both the first and second dorsal abdominal segments mostly black. .40. 

 Either the first, or the second, or both the first and the second dor- 

 sal segments clothed mostly or entirely with yellow pile. ..43. 



40. Scutellum with little or no yellow pile 41. 



Scutellum with mostly or entirely yellow pile 42. 



41. Malar space shorter than its width at apex vosnesenskii. 



Malar space somewhat longer than its width at apex. 



califoruicus. 



42. Squamae of the genitalia extending considerably beyond the tips of 



the volsellse ; the epipygium with little or no ferruginous 



pile iiicaruiii . 



Squamae not extending beyond the tips of the volsellae ; the epipy- 

 gium with considerable ferruginous pile medius. 



43. Both the second and the third dorsal abdominal segments clothed 



with entirely yellow pile 44. 



Either the second or the third dorsal segment clothed in part with 

 black pile 47. 



44. All the dorsal abdominal segments beyond the third reddish-ferru- 



ginous opifex . 



Not more than two of the dorsal abdominal segments bearing red- 

 dish-ferruginous pile 45. 



45. Fourth dorsal abdominal segment entirely yellow 46. 



Fourth dorsal abdominal segment bearing considerable black pile. 



nigrocloi'salis. 



46. First dorsal abdominal segment entirely, or almost entirely, black. 



mecliiis. 

 First dorsal abdominal segment with mostly yellow pile. 



penusylvauicuis. 



47. Malar space distinctly longer than its width at apex. 



californicuis. 

 Malar space about as long as its width at apex brasilieusis. 



48. Apical dorsal abdominal segments with only black hair weisi. 



At least the two apical dorsal abdominal segments clothed largely 



with ferruginous pile (of varying shade) crotchii. 



Species of the Pratorum Group South of the 



United States. 



Boiubus (BombiLs) triiiomiuatus D. T. 



II Bombus modestus Smith, Journ. of Ent., I, 1861, p. 153, n. 4, 9 (not 

 the a ) {nee Cresson, nee Eversmann). 

 Cresson, Proc. Ent. Soc. Phila., II, 1863, p. 109, 

 n. 21-22, 9 , not the S . 



TRANS. AM. ENT. SOC, XXXIX. 



