ART. 2 REVISION OP TRIEHABDA NORTH OF MEXICO BLAKE 23 



uniting at apex, and with metallic luster, most frequently green, 

 but often bluish or purplish or infrequently even piceous. Body 

 beneath pale with darker margins to metasternum and abdomen. 

 Length, 5 mm. to 7.5 mm,; width, 1.8 mm. to 3 mm. 



Type locality. — New Mexico. Collected by Doctor Lewis. 



Distribution. — Montana (Musselshell County) ; Wyoming (Yel- 

 lowstone Park, Rock River) ; Colorado (Custer County, Paonia, 

 Fort Collins, Grand Junction, Creede, Salida, Saguache, Durango, 

 Garland, Colorado Springs, Colbran, Glenwood Springs, Buena 

 Vista) ; Utah (Uinta National Forest, Beaver Range Mountains) ; 

 New Mexico (Taos, Jemez Mountains). 



Food plant. — Ohrysothamnus of the G. nauseosus group (D. H. 

 Blake) . 



Remarks. — Except for the size and coloring of the vittae, this 

 species is subject to little variation. A series of specimens, how- 

 ever, from Creede, Colo. (University of Kansas collection), is 

 very heavily marked, the occipital plaga extending to the eyes, 

 the pronotal spots touching each other, and in some specimens the 

 elytral vittae so wide as to coalesce and produce typical convergens 

 or even attenuata markings. The scutellum is usually bicolored 

 even in the darkest specimens. T. nitidicollis is larger and more 

 robust than lewisii and does not have the wide basal plaga on the 

 head or as large pronotal spots. The pronotum in lewisii is not 

 polished as in nitidicollis., but the elytra resemble those of that 

 species in being finely punctate although more lightly pubescent. 



12. TRIRHABDA NITIDICOLLIS LeConte 



Plate 1, Figures 12, 12a 



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

 219, 1865. 



Description. — Oblong, pale; prothorax shining, not depressed, 

 with small spots; elytra usually with narrow vittae, sometimes 

 piceous, frequently blue, green, or purple. Head finely alutaceous, 

 sometimes with coarse punctation, lightly pubescent over occiput; 

 occipital spot usually with metallic luster, sometimes piceous, wider 

 at base and narrowing down front into a point. Antennae with 

 third joint shorter than fifth. Prothorax large, barely twice as 

 broad as long, obtusely angulate at middle of lateral margin ; surface 

 very polished, sometimes nearly impunctate; spots small, piceous, 

 the median one tending to be diamond -shaped, occasionally eva- 

 nescent. Scutellum bicolored, infrequently entirely pale. Elytra ob- 

 long with broad apex, finely and obsoletely punctate, finely pubes- 

 cent; vittae generally narrow and united at apex, varying from 

 piceous (in many New Mexico and Arizona specimens) to blue or 



