TEIEEHABDA. 485 



different comparative length of the antennae, in which the third joint is nearly always 

 smaller than the fourth ; this latter character the genus has also in common with 

 Nestinus, to which it is in many respects closely allied. The elytra are, in most 

 instances, covered with close and short pubescence ; in some species, however, here 

 described, they are of a metallic colour, with the surface finely rugose ; these species 

 might perhaps have been placed equally well in Nestinus. 



The genus Trirrhabda was established on species inhabiting North America ; none 

 have been described from our country; one species, Galerucella viburni, inhabiting 

 Europe, is placed by Crotch in the present genus. According to Weise (Insect. 

 Deutschl. vi. p. 622) this cannot be the right place for G. viburni, on account of the 

 different general shape and the open anterior coxal cavities ; the latter in Trirrhabda 

 ought to be closed, which is, however, not the case. 



1. Trirrhabda variabilis. (Tab. xxvu. figg. 16, 17.) 



Testaceous or fuscous ; antennae, tibiae, and tarsi black; bead and thorax pale fulvous, tbe former witb one, 

 the latter witb three blackish spots ; elytra green, blue, or violet, finely rugose and pubescent, the lateral 

 margin narrowly flavous. 



Length 3-4 lines. 



Head finely punctured and pubescent, fulvous or testaceous, the vertex with a large blackish or bluish spot ; 

 labrum black ; antennae nearly two thirds the length of the body, black, the third joint distinctly shorter 

 than the fourth; thorax about three times broader than long, rather finely and closely punctured, the 

 disc obsoletely transversely depressed and with a large lateral and also a central black spot ; scutellum 

 black, covered with long pubescence ; elytra clothed with rather long greyish hairs, closely and very 

 finely rugose and punctured, of very variable colour, the lateral margin narrowly flavous, this colour 

 extending to the apex ; underside either flavous or blackish ; tibiae and tarsi of the latter colour. 



Hob. Mexico, Guanajuato, Cuernavaca, La Parada, Puebla, Orizaba, Coscomotepec 

 {Salle), San Miguelito, Hacienda de Bleados, San Luis Potosi (Dr. Palmer) ; Guate- 

 mala (coll. Jacoby). 



Amongst the North- American species described by Leconte, I cannot find any resem- 

 bling the present, on account of the colour of the elytra, e. g. green or blue with the 

 lateral margins narrowly flavous. T. luteo-cincta, from San Diego, is described as 

 having a broad yellow elytral margin, and the thorax remotely and largely punctured. 



Since writing the above I have received, through the kindness of Dr. Horn, a speci- 

 men of T.flavo-limbata, Mann., which is closely allied to, if not identical with, the present 

 species. The North- American specimen differs, however, in the nearly glabrous and 

 shining thorax, and in the colour of the underside, which is metallic greenish and 

 pubescent. The colour and sculpture of the elytra agree with T. variabilis. 



2. Trirrhabda senea. 



Testaceous ; antennae black ; the upper part of the head and three spots on the thorax metallic green ; elytra 

 greenish-aeneous, the lateral and apical margins flavous, the surface finely wrinkled. 



Length 2|-3 lines. 



Head metallic green at the vertex, with a few coarse punctures near the eyes ; the frontal tubercles strongly 

 developed, testaceous, as well as the lower part of the face ; antennae black, the fourth joint longer than 



