HENRY J. FRANKLIN. 245 



42. Dorsum of thorax clouded by a mixture of black and yellow pile..43. 

 Dorsum of thorax with a distinct black interalar band 44. 



43. Femora bearing some yellow pile flavifrons. 



Femora bearing no yellow pile ambiguus. 



44. Abdomen with some segments bearing ferruginous pile. 



centralis. 

 Abdomen without segments bearing ferruginous pile 45. 



45. Third abdominal segment covered above with black pile. 



ambig'uiis. 

 Third abdominal segment covered above with yellow pile. 



centralis. 



46. Second dorsal abdominal segment covered entirely or for the most 



part with ferruginous-red pile 47. 



Second dorsal abdominal segment not covered with ferruginous 

 pile 48. 



47. Pile on anterior part of dorsum of thorax strongly clouded by the 



mixture of yellow and black hairs melanopyg'us. 



Pile on anterior part of dorsum of thorax light yellow, with no 

 black hairs mixed in sylvicola. 



48. Malar space somewhat longer than it is wide at the apex. 



sitkensis. 

 Malar space not longer than it is wide at the apex mixtus. 



49. Abdomen with some segments bearing ferruginous-red pile 50. 



Abdomen with no segment bearing ferruginous-red pile 53. 



50. Dorsum of thorax and vertex of head with black and yellow pile 



mixed, giving a clouded effect ; black band between wings 



not definite nor distinct melanopygvis. 



Front part of thorax above with very little or no black pile mixed 

 with the yellow 51. 



51. Second segment of abdomen entirely covered with yellow pile 



above ; fourth segment with more or less ferruginous-red 



pile above 97. 



Second segment of abdomen with more or less ferruginous-red or 

 black pile above 52. 



52. Pile long and loose ; face generally with a strong tuft of yellow 



between and below the bases of the antennae sylvicola. 



Pile short ; face seldom with a strong yellow tuft as above. 



rufocinctns. 



53. Malar space distinctly shorter than its width at the apex 54 



Malar space not distinctly shorter than it width at the apex 56. 



54. Fourth abdominal segment covered with black pile 55. 



Fourth abdominal segment not entirely covered with black pile. 



rufocinctns. 



55. Ocelli below the supra-orbital line, in the narrowest part of the 



front ; lateral ones nearer to the eyes than to each other. 



morinonoruni. 



TRANS. AM. KNT. SOC, XXXVIII. 



