ART. 2 EE VISION OF TKIRHABDA NORTH OF MEXICO BLAKE 13 



vertex ; alutaceous with dense coarse punctation over occiput, lightly 

 pubescent. Antennae with third joint short and robust, considerably 

 shorter than fifth. Prothorax approximately twice as broad as long; 

 sides only slightly arcuate with small median angle; surface aluta- 

 ceous with sparse, coarse punctures ; pale yellow with the usual three 

 black spots of medium size. Scutellum black. Elytra densely, shal- 

 iowly, and confluently punctate and covered with short, dense, pale 

 pubescence; sutural and wide lateral vittae usually joined after mid- 

 dle (in some Louisiana specimens vittae joined at middle). Body 

 beneath pale with margins of metasternum and abdomen darkened, 

 tarsi also dark. Length, 7.5 mm. to 12 mm.; width, 3.5 mm. to 

 4.5 mm. 



T^j-pe locality. — Eastern North America. 



DistHhution. — New York (Huntington, L. I.) ; Maryland (Chesa- 

 peake Beach) ; District of Columbia (Washington) ; Virginia (Vir- 

 ginia Beach) ; North Carolina (Wilmington) ; South Carolina 

 (Charleston and Holly Hill); Georgia; Florida (Crescent City); 

 Louisiana (New Orleans and Baton Rouge). 



Food jplant. — Groundselbush, BacchaHs halimifolia Linnaeus. 



Remarks. — This species has been known as tonientosa Linnaeus 

 since LeConte identified it with GaXleruca tmnentosa Linnaeus, pos- 

 sibly following Illiger's statement.^ But Linnaeus compares the 

 size of tonientosa with that of G. capreae, the European Lochmaea 

 capreae, a far smaller beetle about 5 mm. long. As this species of 

 Trlrhahda is one of the largest, averaging about 10 mm., it does not 

 seem probable that Linnaeus could have had it before him in writing 

 his description, but rather some species of Galerucella. Weber's 

 description and Olivier's figure, as well as the name indicating the 

 food plant, leave no doubt that Weber's description refers to the com- 

 mon coastal species of Trirhabda of eastern North America found 

 on Baccharis. 



2. TRIRHABDA CANADENSIS (Kirby) 



Plate 1, Figure 2 



Gallcruca canadensis Kikby, Fauna Boreali-Americana, part 4, p. 219, 1837. 

 TrirhaMa canadensis LeConte, Proc. Acad. Nat. Sci. Philadelphia, p. 219, 1865, 

 Trirhabda canadensis vai-. tomentosa Ckotch, Proc. Acad. Nat. Sci. Philadel- 

 phia, vol. 25, p. 56, 1873. 



Description. — Elongate, pale yellow, with darkened antennae and 

 tarsi and sides of abdomen, and with small black occipital and usual 

 pronotal spots ; black sutural and lateral vittae on elytra narrow and 

 joined at apex. Head alutaceous with coarse punctures, moderately 

 pubescent, an oblong black spot on occiput extending down front. 



8 Mag. fiir Insektenkunde, vol. 6, p. 146, 1807. 



