ISAMINAS.—HEGEMONA. 267 
1. Isaminas gibbipennis, (Tab. XI. fig. 21,2.) 
Isaminas gibbipennis, F. Bates in litt. 
Black, with a very faint bronzy tinge, slightly shining. Head sparingly and finely punctured, often with two 
shallow impressions between the eyes; prothorax with the sides broadly rounded anteriorly, almost 
straight (sometimes slightly sinuous and irregular) from the middle to the base, the hind angles sub- 
rectangular, the base rather strongly margined, the dise with a distinct central groove and usually with a 
rounded fovea on each side about the middle, the surface almost impunctate; elytra with rows of coarse 
rounded impressions; beneath smooth, shining; prosternum very broad, parallel, strongly produced, 
deeply longitudinally grooved on each side within, the central convex part slightly extended and 
received by the concave mesosternum ; epipleure distinctly separated from the elytra and rather broadly 
extended to the apex ; legs black. 
Length 9-114 millim.; breadth 6-7 millim. (¢ 9.) 
Hab. Nicaraaua (Sallé, coll. F. Bates), Chontales (Belt, Janson); Costa Rica 
(Sailé). 
Numerous examples. 
2. Isaminas brevicollis. 
Closely allied to I. gibbipennis and only differing as follows :—the antenne in the female not quite so short 
and with the ninth and tenth joints less transverse; the prosternum less parallel, broadly and acuminately 
produced and-received by the deeply excavate V-shaped. mesosternum ; epipleure confounded with the 
flanks of the elytra and only defined therefrom at the base. 
Length 83-11 millim. (¢ 9.) 
Hab. Guatemata, Senahu, San Juan in Vera Paz, Sinanja (Champion). 
Many examples. This insect, though extremely similar to 1. gibbipennis, differs con- 
stantly in the structure of the prosternum and elytral epipleure ; I am obliged to treat 
it as a distinct species. In Guatemala it appears to be confined to the Atlantic slope, 
to the vicinity of the Polochic valley and the humid forest-clad mountain-range north 
thereof; it is found at an elevation of from 1500 to 3000 feet. 
HEGEMONA. 
Hegemona, Castelnau, Hist. Nat. Ins. Col. ii. p. 280 (1850); Lacordaire, Gen. Col. v. p. 448 ; 
Allard, Monogr. in Mittheil. der schweiz. ent. Ges. v. pp. 60 & 251 (1880). 
This is probably the most characteristic genus of Central-American Tenebrio- 
nide. Seven species have been described, six from Central America and one from 
Colombia; we have now to record seventeen, no less than eleven of which appear to be 
new. ‘Two only were described previous to the publication of M. Allard’s monograph 
of the genus; Lacordaire (op. cit. p. 449, nota), however, in addition to the two former 
briefly notices two other species from Mexico. Besides the large number of specimens 
before me, I have examined many others in the British and Stuttgart Museums, and 
also in the collection of M. Réné Oberthir. ‘The species are all of large size, and are 
the giants of the section Helopide. The males usually have the anterior tarsi more 
dilated than the females, the thorax rather longer, &c. ; the females in some few species 
2 MM 2 
