244 LAWRENCE BRUNER. 



52. Larger species (10-12 mm.) 53. 



Smaller species (5-9 mm.) 58. 



53. Stigma comparatively small 54. 



Stigma normal .55. 



54 Wings clear hyaline ; abdomen minutely tessellate Itarlx-ri Ckll. 



Wings whitish ; abdomen rather finely punctured, the apical portions of seg- 

 ments rather broadly pale testaceous heliaiillii Rob. 



55. Abdomen without punctures, the head of moderate width A licia' Rob. 



Abdomen punctured, the head rather large 56. 



56. Head broader thad thorax, the apical margins of abdominal segments broadly 



pale testaceous reflex a Cress. 



Head and thorax about equal in width 57. 



57. Abdomen covered with fine, short, appressed hairs which form bands on seg- 



ments 4 and 5 fra<*ta Casad. & Ckll. 



Abdomen without hair bands, flies late in the spring Kincaidii Ckll. 



58. Pubescence on thorax ochraceous or pale fulvous 59. 



Pubescence on thorax gray or white ... -60. 



59. Head and thorax clothed with ochraceous pubescence- • -clypeolala D. T. 



Pubescence on head and thorax inclining to fulvous SCutellata D. T. 



Clypeus with a large trilobed yellow spot krigiana Rob. 



60. Flagellum of antennae testaceous or ferruginous beneath 61. 



Flagelluin of antennas darker, brown or black beneath 63. 



61. Nervures brown. Segments 2-4 of abdomen with very distinct white bands. 



simulata Prov. 

 Nervures of wings lighter, honey yellow or testaceous - 62. 



62. Cheeks narrow, convex, regularly rounded ; enclosure unusually broad and 



rough; abdomen finely sparsely punctate; clypeus yellow. 



Robertsonii D. T. 

 Cheeks broad, flat, subtriangular, with rounded angles behind middle of eye; 

 enclosure small, finely rugose, except basal middle; abdomen almost 

 impunctate ; clypeus and sometimes spot on each side of face yellow. 



bipunctata Cress. 



63. Clypeus chrome yellow; abdomen finely punctate, flies in spring. 



Trevoris Ckll 

 Clypeus pale yellow; abdomen impunctate, flies in the fall. 



solitlaginis Rob. 



64. Abdomen without well defined hair bands 65. 



Abdomen provided with more or less complete hair bands 120. 



65. Abdomen smooth, shining, almost without pubescence 66. 



Abdomen more or less thickly and evenly covered with pubescence 109. 



66. Pubescence entirely black 67. 



Pubescence more or less fulvous, ochraceous, testaceous or cinereous 70. 



67. Thorax with the pubescence dense, hiding the surface 68. 



Thorax with the pubescence rather sparse, not hiding the surface 69. 



68. Insects larger (17i mm. in length) ; wings purplish fuliginous., valiria Say. 

 Insects smaller (13 mm.) ; wings smoky red nigra Prov. 



69. Wings dusky hyaline; abdomen closely and finely punctured. 



nigerriiua Casad. 

 Wings yellowish hyaline, abdomen practically impunctate. .I'ortera? Ckll. 



