ABT, 19. AMERICAN BEES OF THE GENUS HALICTUS — SANDHOUSE. 5 



52. Head narrow; fiagellum clear ferruginous; disk of propodeum polished. 



semibrunneus Cockerell. 

 Head normal; flagellura dark; disk of propodeum faintly granular with fine 



radiating plicae (Eastern States) sparsus Robertson. 



Disk of propodeum not granular; mesothorax more coarsely punctured 



(Western States) sparsus, variety Ellis MSP. 



53. Mesothorax polished, delicately punctured; disk of propodeum weakly pli- 



catulate on base only exiguus Smith. 



Mesothorax opaque; sculpturing of disk of propodeum, not confined to base. . 54 



54. Mesothorax with sparse shallow punctures; disk of propodeum plicate (Massa- 



chusetts) admirandus, new species. 



Mesothorax more closely punctured; disk of propodeum rugose (Nevada). 



nevadensis Crawford. 



55. Tegulae dark; wings dusky; stigma dark 56 



Tegulae light; or if somewhat dark, wings not dusky 63 



56. Head and thorax brassy or bronze green; abdomen with bronze reflections; 



disk of propodeum plicate on base only (Guatemala) umbripennis Ellis. 



Head and thorax not so 57 



57. Mesothorax polished, sparsely punctured; disk of propodeum with weak pli- 



cae largely confined to base (Colorado) tenax, new species. 



Mesothorax opaque, more closely punctured 58 



58. Mesothorax very closely punctured, giWng a granular appearance; disk of 



propodeum granular, apex polished (Colorado and New Mexico). 



ruidosensis Cockerell. 

 Mesothorax not so closely punctured; disk of propodeum not granular. 59 



59. Larger; mesothorax very coarsely punctured; disk of propodeum very sharply 



truncated, with coarse plicae (New Jersey) oceanicus Cockerell. 



Smaller; not so sculptured 60 



60. Abdomen and legs brown; mandibles red; disk of propodeum with radiating 



rugulae (Grenada, W.I.) sanctivincenti Ashmead. 



Abdomen and legs black; mandibles dark 61 



61. Fiagellum dusky ferruginous; disk of propodeum short, the plicae not reach- 



ing the apex, which is polished (Maine) versans Lovell. 



Fiagellum black; plicae reaching the apex of disk of propodeum, which is 

 longer (Colorado) 62 



62. Mesothorax with shallow, scattered punctures; apical margins of abdominal 



segments testaceous; abdomen narrower at base pacatus, new species. 



Mesothorax quite closely punctured; apical margins of abdominal segments 

 black; abdomen broad at the base viridatulus Cockerell. 



63. Wings clear white; pubescence pure white, abundant 64 



Wings more or less yellowish; pubescence more sparse, dull or yellowish white. . 67 



64. Mesothorax very coarsely punctured; disk of propodeum with somewhat dis- 



continuous plicae; abdomen black albipennis Robertson. 



Mesothorax not so coarsely punctured ; abdomen brown 65 



65. Smaller; mesothorax blue, delicately punctured; disk of propodeum reticu- 



lated (New Mexico) alius, new species. 



Larger; mesothorax golden green, closely punctured; disk of propodeum not 

 reticulated 66 



66. Disk of propodeum brilliant blue, granular (New Mexico), .perdifficilis Cockerell. 

 Disk of propodeum color of mesothorax, plicate, polished at the apex (Leth- 



bridgeAlta.) laevissimus Smith. 



67. Face subquadrate; inner orbits arched above; clypeus and supraclypeal area 



polished 68 



Not so; head narrow or subcircular 69 



