REVISION OF THE SPECIES OF BEETLES OF THE 

 GENUS TRIRHABDA NORTH OF MEXICO 



By Doris Holmes Blake 



Assistant Entomologist, Bureau of Entomology, United States Department of 



Agriculture 



INTRODUCTION 



The genus Trirhabdai of the Chrysomelidae was described by 

 LeConte^ in 1865, and to it were assigned nine North American 

 species, all of which are still commonly retained in the genus. They 

 are, in order: T. nitidicoUis, new species, T. {Galleruca) canadensis 

 Kirby, T. (Galleruca) luteocincta LeConte, T. {Galleruca) flavo- 

 lirribata Mannerheim, T. {Gallei^uca) attenuata Say, T. convergens, 

 new species, T. (Ghrysoniela) tomentosa Linnaeus, T. virgata^ new 

 species, and T. hrevicoUis^ new species. No type has hitherto been 

 designated for TrirJiabda. In a discussion of the typification of 

 THrhahda and some related genera contributed by H. S. Barber to 

 the present paper (pp. 2-3), the first species, nitidicollis, is selected as 

 the type of LeConte's genus. LeConte's ninth and last species, hrev- 

 icollis, differs from the others in many characters and is made, on 

 page 32 of this paper, the type of a new genus. 



LeConte characterized the genus as having the body large, elon- 

 gate, not very convex, finely punctured, and pubescent ; the head not 

 at all carinate in front, the antennae with the third joint shorter 

 than the fourth; the prothorax with a transverse impression; the 

 elytra margined, with epipleura extending only halfway; the 

 tibiae not sulcate; and the claws cleft. The usual color he de- 

 scribed as pale, with a black occipital spot on the head, three dis- 

 coidal spots on the prothorax, and broad sutural and discoidal black 

 or green stripes on the elytra, these vittae coalescing in some species 

 and leaving only the margin pale. He separated the genus from 

 GaleruceUa and Monoxia by a difference in the proportion of the 



1 Proc. Acad. Nat. Sci. Philadelphia, vol. 17, p. 219, 1865. The exact date of publi- 

 cation of the number (for "October") in which LeConte's paper appeared Is not Ijnown. 

 The only available information is given in the note in the Index of the Contents of the 

 Journal and Proceedings of the Academy, 1913: Vol. 17 (1865), no. 4 (pp. 173-236). 

 " Receipt acknowledged by Albany Institute, Dec. 26, 1865." 



No. 2868.— Proceedings U. S. National Museum, Vol. 79. Art. 2. 



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