X2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.79 



Elytra with fine, white pubescence; prouotal spots small, 

 median one situated nearer base of pronotum than anterior 

 margin ; lateral and sutural vittae usually coalescing behind 

 middle, rarely the attenuated median pale vitta exteudi)ig 

 much below middle attenuata (p. 21) 



26. Large (6 mm. to 8 mm.) ; elytral vittae very dark, appearing 



black, but with indistinct blue, purple, or, rarely, green hue; 



abdomen mostly pale borealis indigoptera, new variety (p. 17) 



Smaller (5 mm. to 6.5 mm.) ; elytral vittae or entire elytra (in 

 species with elytra dark except for margin) with green or 

 blue luster, more or less pronounced ; abdomen always dark 27 



27. Elytral vittae inconspicuously green or blue, appearing nearly 



black. Nova Scotia neoscotiae, new species (p. 17) 



Elytral vittae or entire elytra except for margin with distinct 



metallic luster. Great Lakes westward 28 



28. Elytra usually entirely blue or green, the vittae in vittate 



forms usually not united at apex ; elytra only moderately 

 pubescent ; body beneath dark without metallic luster, paler 

 in vittate forms. Great Lakes, Wisconsin, Manitoba, Alberta. 



vlridicyanea, new species (p. 19) 

 Elytra entirely green except for margin, or in vittate forms 

 with wide lateral and sutural vittae united at apex ; elytra 

 densely pubescent ; body beneath dark with metallic luster. 

 Rocky Mountains convergens (p. 18) 



29. Elytra coarsely punctate, very spai'sely pubescent caduca (p. 31) 



Elytra not coarsely punctate, finely and den.sely pubescent 30 



30. Pronotum densely and coarsely punctate ; elytra usually with 



median vitta or traces of it, or entirely reddish brown or 



piceous geminata (p. 31) 



Pronotum sparsely and coarsely punctate; elytra never with 



median vitta or entirely dark 31 



31. Prothorax not angulate, alutaceous ; elytra with only small 



dark humeral spot, not with metallic luster; small (5 mm. 



to 7 mm.). Arizona and New Mexico nigrohumeralis (p. 30) 



Prothorax usually angulate, shining; elytra usually with elon- 

 gate humeral spot, and usually with metallic luster ; larger 

 (5 mm. to 9 mm.). Southern California eriodietyonis (p. 24) 



1. TRIRHABDA BACHARIDIS (Weber) 



Plate 1, Figure 1 



Oalleruca bacharidis Weber, Observationes Eutomologicae, p. 57, 1801. — 



Fabbicius, Syst. EL, vol. 1, p. 480, 1801.— Olivier,, Ent., vol. 6, p. 629, 



pi. 3, fig. 34, 1808. 

 Trirhabda tomentosa LeConte, Proc. Acad. Nat. Sci. Philadelphia, vol. 17, p. 



220, 1805. Probably not Qallcruca tomentosa Linnaeus, Syst. Nat., ed. 12, 



vol. 1, pt. 2, p. 601. 



Description. — Robust, subparallel, pale yellow, with darkened an- 

 tennae and tarsi, black occipital and three thoracic spots, and wide 

 lateral vitta joining with sutural vitta below middle. Head pale 

 with dark mouth parts and occipital plaga extending narrowly down 



