322 PHYTOPHAGA. 



tibise, which I find in the type as well as in the other Mexican specimens I have for 

 examination. In this character the genus agrees with Casporis and also with Systena, 

 which latter genus is so closely allied to Prasona that it may perhaps rightfully be 

 incorporated with it. There is, however, a decided difference to be found in the 

 structure of the antennae in Prasona, which, at least in the male insect, are robust at 

 the base and tapering towards the apical joints, and the third joint is longer than the 

 fourth, not equal, as Von Harold says (Coleopt. Hefte, xv.). In System these joints are 

 very nearly equal in length, the third joint being sometimes slightly shorter. I think 

 that it is therefore desirable to retain the name of Prasona for the species which forms 

 the type, on account of its large size, peculiar coloration, and the structure of the 

 antennae, which make the insect easy of recognition. 



l. Prasona viridis. (Tab. xix. fig. 13.) 



Prasona viridis, Baly, Journ. of Entom. i. 1861, p. 301 \ 



Eab. Mexico \ Toxpam, Cordova (coll Salle), Jalapa {Edge). 



I may add to the description of Mr. Baly that the antennae in the male insect are 

 much more robust than in the female, and that they are distinctly thickened at the 

 base and gradually tapering towards the apex. The species does not seem to be a very 

 common one, only three specimens having been obtained by Herr Hoge ; six others are 

 contained in the collection of M. Salle. 



SYSTENA. 

 Systena, Clark, Journ. of Entom. i. 1865, p. 402. 



The typical species of this genus are for the most part small and similarly coloured, 

 having dark elytra with one or two longitudinal pale stripes. Many other coloured 

 forms from Central America are, however, before me, some of which at the same time 

 are much larger in size. I have already dwelt upon the close affinity of this genus 

 and Prasona in my remarks on the latter genus, and have also pointed out the presence 

 of a small spine at the apices of all the tibise in both genera. The shape of Systena is 

 for the most part peculiar to the genus ; the elytra are somewhat flattened above and 

 widened behind in nearly all the larger-sized species, more convex and parallel, how- 

 ever, in those of smaller size. The antennae seem, moreover, never to decrease towards 

 the apex in thickness, as in Prasona, but remain of equal size, or are thickened at the 

 terminal joints. The species constituting the present genus are distributed from North 

 to South America, as well as in some of the West- Indian islands. Up to the present 

 time but two species have been described from Central America. 



1. Systena marginata. (Prasona marginata, Tab. XVII. fig. 21.) 



Fulvous ; thorax and elytra finely punctured, the latter metallic blue or green, the lateral margin and apex 

 narrowly fulvous. 



Length 3| lines. 



