264 HETEROMERA. 
* Prosternum horizontal, broadly and strongly produced, the apex raised and 
received by the moderately concave V-shaped mesosternum. 
1. Oxidates planicollis. (Tab. XI. figg. 19,6; 194, labium; 194, maxilla 
and maxillary palpus; 19c, cedeagus. 
Black, with a slight bronzy tint, moderately shining. Head very sparingly, finely, and shallowly punctured ; 
antenne long and slender; prothorax transverse, comparatively very broad, rounded at the sides, if any- 
thing rather more narrowed anteriorly than at the base, the sides in some examples constricted immediately 
before the base and with the hind angles acute, and in others less rounded and narrowing more obliquely 
before and behind the middle, the anterior angles broadly and obtusely rounded, the base distinctly but 
comparatively not very strongly margined, the disc somewhat flattened and often with a shallow rounded 
fovea on each side a little before the middle, the surface exceedingly finely, shallowly, and rather closely 
punctured ; scutellum comparatively large and distinct ; elytra abruptly constricted behind and with the 
apex rather broadly produced, with rows of coarse scattered rounded impressions, the impressions finer 
and shallower along the basal half of the suture ; beneath shining, almost smooth ; prosternum horizontal, 
smooth, broadly and longitudinally excavate within, broadly and strongly produced, the apex rounded, 
raised, and received by the moderately deeply excavate V-shaped mesosternum ; epipleure ending at the 
last ventral suture ; intercoxal process very broad, narrowly margined anteriorly; legs black. 
Length 11-14} millim. (¢ 9.) 
Hab. Mexico, Misantla (Hége). 
Found in abundance by Herr Hége at Misantla. This species will be at once known 
from its allies by the flatter and broader thorax, the base of which is not so strongly 
margined, and the differently formed pro- and mesosternum. 
** Prosternum very broad, subhorizontal, the apex not raised ; mesosternum 
broadly and very feebly excavate. 
2. Oxidates gravidus. 
Spherotus gravidus, de Bréme, Revue Zool. 1842, p. 109°. 
Hab. Mexico ! (coll. Brit. Mus.), Cordova (Sadie). 
In this species the numerous large and coarse though comparatively shallow impres- 
sions on the elytra each bear a smaller impression in the centre. 
3. Oxidates thoracicus. 
Spherotus thoracicus, de Bréme, Revue Zool. 1842, p. 110°. 
Hab. Mexico! (coll. Brit. Mus.), Tuxtla, Playa Vicente, Cordova (Sallé), Misantla 
(Hoge). 
Several specimens before me agree very fairly with the description, except that they 
have the thorax very minutely and shallowly punctured instead of “lisse”; I notice, 
however, the punctuation of the head and thorax varies in intensity, and consequently 
have little doubt our insects are referable to de Bréme’s species. The thorax is 
