284 PHYTOPHAGA. 



Hab. Guatemala, Duenas (Champion); Costa Rica, Volcan de Irazu (Bogers). 



The rather abnormal structure of the head, the groove of the thorax, which is placed 

 close to the posterior margin, and the almost black colour of the entire insect will assist 

 to distinguish it, Five specimens were obtained. 



PLECTROTETRA. 



Plectrotetra, Baly, Journ. of Entom. i. p. 454 (1862). 



The only species constituting up to the present time Mr. Baly's genus is well charac- 

 terized by the shape of the thoracic groove, which gradually approaches the posterior 

 angles (not being bounded at the sides by a longitudinal groove), by the robust antennae 

 in the male, and the bifid claws. The type (P. clarki) is, moreover, of easy recognition 

 on account of its size and sculpture of the elytra. Many new species, however, have 

 now been obtained by Mr. Champion and Herr Hoge, some of which seem to be of very 

 variable punctuation as regards the elytra, and altogether very difficult to separate into 

 species. I have taken as a principal distinctive character the comparative length of the 

 joints of the antenna? in the male, as this seems to be a more constant character than 

 the punctuation of the elytra. 



1. Pletrotetra clarki. (Tab. XVI. figg. 24, 25.) 



Plectrotetra clarki, Baly, Journ. of Ent. i. p. 455 (1862) 1 , tab. xxi. fig. 3. 

 Diphaulaca rugipennis, Sturm, Cat. 1843, p. 282. 



Hab. Mexico, Oaxaca 1 , Yolotepec, Capulalpam (Salle); Guatemala, San Juan, 

 Sinanja in Vera Paz, Calderas (Champion) ; Panama, Volcan de Chiriqui (Champion). 



This is the largest species of the genus, the male of which may be known by the 

 robust antennae, the third joint of which is much larger than the fourth; the elytra in 

 the same sex have three or four double rows' of punctures, the interstices of which 

 are somewhat convex and broad. In the female the antennae are much shorter, 

 thinner, and the third and fourth joints are of nearly equal length; the elytra are 

 longitudinally costate, and the interstices finely transversely rugose and punctate ; of 

 the ridges, three are generally more raised than the others, wider apart, and somewhat 

 curved, which characters will help to separate the female of the present species from 

 closely allied forms. The specimens from Guatemala are smaller than the Mexican 

 insects, but in other respects similar. 



2. Plectrotetra dohrni. 



cJ. Fulvous; antennse, their basal joints excepted, black; elytra metallic green, strongly and subgeminate 



punctate-striate, the interstices towards the apex costate. 

 $ . Elytra more finely and more regularly geminate punctate-striate, each elytron with three more strongly 



raised costae, which are depressed posteriorly more or less. 

 Length 2| lines. 



