HENRY J. FRANKLIN, 251 



Only the apical abdominal segment black ; clypeus smooth and 

 shining appositus. 



20. Pile over the greater part of the thoracic dorsum of black and yel- 



low hairs mixed, giving a clouded appearance 21. 



This pile not appearing clouded ; black interalar band rather dis- 

 tinct 24. 



21. Pile on scutellum conspicuously lighter than that on any other part 



of the dorsum of the thorax iiielanopyg-lis. 



Pile on scutellum not conspicuously lighter than that on anterior 

 part of the thorax above 22. 



22. The apical segments of abdomen covered above with light or ferru- 



ginous pile, or at least with such pile very strongly inter- 

 mixed 23. 



The two apical segments of abdomen above not covered with light 

 or ferruginous pile flavifron S. 



23. Length of malar space greater than its breadth at the apex. 



sitkensis. 

 Malar space about as broad at the apex as it is long mixtus. 



24. Pile very long and loose sylvicola. 



Pile not very long and loose 25. 



25. Second dorsal abdominal segment entirely covered with yellow pile. 



centralis. 



Second abdominal segment not entirely covered above with yellow 



pile 26. 



26. Yellow pile on face not very noticeable, sometimes entirely absent. 



rufocinctus. 

 Yellow pile on face very noticeable 27. 



27. Fringes of corbiculse usually with a distinct ferruginous tinge ; 



black interalar band extended posteriorly in the middle so 

 as to divide or nearly divide the yellow of the scutellum. 



edwardsii. 



Fringes of corbiculse usually black and without a ferruginous tinge ; 



posterior border of black interalar band running straight, or 



nearly so, across the thorax 28. 



28. Second and third abdominal segments with black pile above. 



fernaldi. 

 Second and third abdominal segments covered with yellow or fer- 

 ruginous-red pile above liuntii. 



29. Pleura, or at least their lower parts, covered with black pile or so 



shaded by the admixture of dark hairs {polaris often ex- 

 cepted) as to be noticeably darker than the front part of the 

 thoraxabove ; yellow pile not reaching the bases of the legs..30. 

 Pleura covered with yellow pile to bases of legs 31. 



30. Dorsum of thorax entirely covered with yellow pile except, perhaps, 



a small dark spot in the center ; no black interalar band. 32. 



TRANS. AM. ENT. SOC, XXXVIII. 



