AET. 2 REVISION OF TMEHABDA NORTH OF MEXICO BLAKE 3 



Galeruca Geoffrey, 1762. 5 species without names, but the first one with cita- 

 tation to the species chosen by Latreille. 

 Genotype, Chrysomela ianaceti Linnaeus, 1758, designated by Latreille, 

 1810. 

 Gallcriica Fabricius, 1792 (emendation of Galeruca). 



Coelomera Chevrolat. in De.lean. 1837, 31 species, most of them with invalid 

 specific names. The species chosen for type of this genus as described 

 by Chevrolat, 1844, is acceptable for its earlier establishment in the 

 Dejean Catalogue. 

 Genotype Chrysomela cayennensis Fabricius, 1789, designated by Weise, 

 1924. 

 Monocesta Clark, 1865 (October 1), 24 species. 



Genotype, Monocesta impcrialis Clark, 1865, designated by Weise, 1924. 

 Coroia Clark, 1865 (October 1), 1 species. 



Genotype, Coraia rnaculicollis Clark, 1865, monobasic. 

 Nestinus Clark, 1865 (October 1), 3 species. 



Genotype, Nestinus Mmaculatns Clark, 1865, present designation. 

 Trlrhahda LeConte, 1865 (October ?), 9 species. 



Genotype, Trirhahda nitidieollis LeConte, 1865, present designation. 

 Pyrrhalta Joannis, 1866, 1 (?) species. 



Genotype, Galleruca vibnrni Payk, 1778, monobasic (?). 

 Trihabda Crotch, 1873 (typographical error). 

 TrirrJiabda Gemminger and Harold, 1876 (emendation or typographical error). 



DESCRIPTION OF THE GENUS 



The head in Trlrhabda is punctate and pubescent on the occiput 

 and vertex. The occipital spot is sometimes only a narrow darkened 

 line down the vertical fovea that is present in all species, or it may 

 cover the entire base of the head and partly encircle the eyes. Yet 

 in all species except two * that have been hitherto placed in 

 Trirhahda, this occipital spot is present, and its shape, size, and color 

 are of considerable specific importance. The antennal joints are 

 variable, with the fourth always longer than the third. The third 

 and fifth antennal joints are usually not equal, although in a given 

 species they may vary slightly. 



The prothorax in most species appears transversely depressed, but 

 this may be due to the collapse of soft tissues. It is usually ap- 

 proximately twice as broad as long, sometimes less, rarely more. 

 The margin as viewed from above is usually arcuate, but may be 

 distinctly angulate medially. The apical and the basal angles have 

 a tiny nodule. The surface is usually either alutaceous or shining 

 with scattered coarse punctures, rarely impunctate; sometimes it is 

 pubescent. It is pale j^ellow or brown and always has three spots 

 varying in size, color, and shape, two lateral and one median. 



The color of the scutellum is an important character also. In 

 species in which the pale color predominates, the scutellum is often 

 bicolored. 



* T. brevicollis and T. ornata — here referred to a new genus ; see pp. 33, 34. 



