14 PROCEEDIlSrGS OF THE NATIONAL MUSEUM vol. 79 



Antennae with third joint shorter than fifth. Prothorax not twice 

 as broad as long, with sides slightly arcuate, angles small, not prom- 

 inent; surface alutaceous with scattered coarse punctures; spots 

 small and black, median one tending to be diamond-shaped. Scutel- 

 lum entirely black. Elytra densely but finely punctate, and cov- 

 ered with dense pale pubescence; lateral and sutural vittae only 

 moderately wide and usually united at apex. Body beneath mostly 

 pale, frequently with dark margins to metasternum and abdomen. 

 Length, 7 mm. to 10 mm. : width, 3 mm. to 4 mm. 



Type locality. — Canada. Collected by Doctor Bigsby, probably 

 north of the Great Lakes or the St. Lawrence River. 



Distribution. — Ontario, Manitoba, Saskatchewan, Alberta, British 

 Columbia, Maine, New Hampshire, Massachusetts, Rhode Island, 

 Connecticut, New York, New Jersey, Pennsylvania, Maryland, 

 West Virginia, Michigan, Illinois, Kansas, Nebraska, South Dakota, 

 Montana, Idaho, Colorado, Wyoming, Utah, Nevada, Arizona, New 

 Mexico, California (" Siskiyou "), and Washington. 



Food plant. — Goldenrod, Solidago. 



Remarks. — This is probably the most widespread species of the 

 genus, although its occurrence in the southern Atlantic and Gulf 

 States has not been recorded. It is unlikely that Kirby's descrip- 

 tion applies to any other species, as there is no vittate northern 

 Trirhahda, except this species, having a " dot " for an occipital spot. 

 It varies little in markings in its wide range. The lateral and 

 sutural vittae are usually united at the apex; the occipital and 

 pronotal spots are small. The dense elytral pubescence and fine 

 punctation at once distinguish it from virgata., while the somewhat 

 depressed and finely alutaceous pronotum distinguishes it from 

 nitidicolJis with its polished, smooth pronotum. 



3. TRIRHABDA ADELA, new species 



Plate 1, Figure 3 



Description. — Of same general appearance as T. canadensis, but 

 usually with a broad black plaga extending across occiput and larger, 

 rounded spots on pronotum ; pronotum also with more arcuate sides, 

 and elytral vittae not united. Head coarsely, rugosely punctate, 

 moderately pubescent, with wide black plaga extending across occi- 

 put and down front. Antennae with third joint shorter than fifth. 

 Prothorax about twice as broad as long with arcuate sides and feeble 

 angles ; alutaceous with scattered coarse punctures ; spots larger and 

 rounder than in canadensis. Scutellum black. Elytra a little more 

 coarsely punctate than in canadensis, densely and finely pubescent; 

 black sutural and lateral vittae moderately wide and usually not 

 united at apex. Body beneath sometimes with abdomen entirely 



