SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE, VOL. xxxni. 



PLATE 28. 





FIG. 2. 



FIG. 3. 



FIG. 4. 



FIG. 5. FIG. 6. 



BAL&NOPTERA DAVIDSONI, ACUTO-ROSTRATA, AND VELIFERA (?). 



Figs, i and 2.B. (iavidsoni, Valdes, Alaska. Figs. 3 and 4. B. acato-rostrata, Quoddy Head, Maine. Figs. 5 and 6. B. velifera(~t), California. 



