ART. 2 REVISION OF TRIEHABDA NORTH OF MEXICO BLAKE 21 



abdomen, except for last segment, dark with metallic luster and 

 densely pubescent. Legs with outer edge darkened. Length, 4.5 

 mm. to 6.8 mm. ; width, 1.8 mm. to 2.8 mm. 



r?/;?e.— Collected by D. H. Blake, September, 1927, at Mammoth, 

 Yellowstone Park, Wyo. U. S. N. M. No. 43021 (with 71 para- 

 tyi^es). Four paratypes each in collections of C. A. Frost, F. S. 

 Carr, H. P. Loding, Museum of Comparative Zoology, Academy of 

 Natural Sciences of Philadelphia, Illinois State Natural History 

 Survey, and University of Kansas. 



Distribvjtion. — Wyoming, Nevada, California (Nevada County, 

 Truckee, Tallac, Lake Tenaya, Yosemite). 



Food plant. — Sagebrush, Artemisia tridentata Nuttall (D. H. 

 Blake). 



ReTimrks. — This small species somewhat resembles attenuata in 

 elytral markings, and has been confused with it. It is smaller than 

 attenuata^ and the dense white pubescence of the prothorax, as well 

 as the larger pronotal spots, at once differentiates it. The elytra are 

 yellowish green rather than bluish green, as is more often the case 

 in attenuata, and the median vitta rarely reaches the middle of the 

 elytra, whereas in attenuata it attains the middle and not infrequently 

 extends nearly to the apex. The ventral surface of pilosa is also 

 much darker than in attenuata. Its range also is different, as it 

 occurs from Wyoming to the Sierra Nevada in California, while 

 attenuata is found from the Great Plains to the Rocky Mountains. 



10. TRIRHABDA ATTENUATA (Say) 



Plate 1, Figure 10 



Galleruca attenuata Say, Journ. Acad. Nat. Sci. Philadelphia, vol. 3, p. 459, 



1824. 

 Trirhabda attenuata LeContb, Proc. Acad. Nat. Sci. Philadelphia, vol. 17, p. 



220, 1865. 



Description. — Elongate, finely punctate, lightly pubescent; pale 

 yellow with wide black plaga over occiput, pronotum with usual 

 three spots, elytra with wide blue or green lateral and sutural vittae 

 coalescing usually at middle and leaving only an attenuated pale 

 vitta, wider at base, on either elytron. Head rugosely punctate over 

 occiput, moderately densely pubescent, a wide dark plaga with usu- 

 ally green luster across base of head curving down over front. 

 Antennae with third joint shorter than fifth. Prothorax approxi- 

 mately twice as wide as long, with arcuate sides, shining, with 

 scattered coarse punctures, surface sometimes lightly pubescent; 

 spots small, median one situated nearer base than anterior margin. 

 Scutellum frequently with paler outer margin. Elytra finely punc- 



