24 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 79 



green (particularly well marked in Montana, Idaho, and some Cali- 

 fornia specimens). Body beneath entirely pale. Length, 7 mm. to 

 9 mm.; width, 2.8 mm. to 3.8 mm. 



Type locality. — New Mexico. Collected by Fendler. 



Distribution. — Montana (Dillon) : Idaho (Soda Springs) ; Wy- 

 oming (Yellowstone Park) ; Colorado (Sedalia, Canon City) ; Utah 

 (Beaver Canyon) ; Nevada (Esmeralda) ; New Mexico (Lamy) ; 

 Arizona (Bright Angel, Squaw Springs) ; California (Los Angeles 

 County, Chino Canyon, Lebec, Bishop). 



Food plants. — Gutiei^'ezia sarothrae (Caudell), Chrysothamnus 

 of the C. nameosus group (D. H. Blake), sagebrush, Artemisia sp. 

 (R. Hopping). 



Remarks. — This species is distinguished by its large, polished, 

 and not depressed prothorax. A series of specimens from Los An- 

 geles County, Calif., collected by Coquillett, and a series from Es- 

 meralda, Nev., present considerable variation. They are smaller 

 (6 mm. to 8 mm.), with less well-defined vittae, which do not join 

 at the apex; the pronotum is somewhat depressed and has scattered 

 coarse punctures, contrasting with the polished, nearly impunctate 

 surface of typical nitidicoUis., and the spot on the head is larger. 



13. TRIRHABDA ERIODICTYONIS Fall 



Pl:;te 1, Figure 13 

 TrirhaMa eriodictyonis Fall, Can. Ent., vol. 39, p. 243, 1907. 



Description. — Elongate, dull yellow-brown, head with a narrow 

 occipital spot; prothorax 3-spotted, shining, angulate; elytra usually 

 with darkened humeral spot or this occasionally extended into lateral 

 vitta having a metallic luster. Head densely and moderately 

 coarsely punctate, with pale light pubescence; a narrow, sometimes 

 linear, black spot down vertex, broader in male. Antennae with 

 third joint slightly shorter than fifth. Prothorax twice as broad as 

 long, usually with prominent median angle on lateral margins; sur- 

 face shining with only sparse coarse punctures; spots small and 

 tending to be diamond-shaped. Scutellum pale, usually with narrow 

 piceous margin at base. Elytra elongate, somewhat narrowed to- 

 ward apex, densely and finely punctate, with fine, dense, short but not 

 conspicuous pubescence. A dark humeral spot, sometimes extending 

 into a narrow lateral vitta with greenish metallic luster. Body 

 beneath entirely pale. Length, 5 mm. to 9 mm.; width, 1.8 mm. to 

 3.5 mm. 



Type locality. — '• Pasadena, San Bernardino, and elsewhere in 

 southern California." 



