276 HETEROMERA. 
strongly angularly raised interstices, the finely punctured strie, and the very brilliant 
bronzy upper surface; the numerous specimens before me vary in size from 20-243 
millimetres. I have not seen this insect from Costa Rica. 
DINOMUS. 
Dinomus, de Bréme, Revue Zool. 1842, p. 118; Lacordaire, Gen. Col. v. p. 444. 
This genus was established by the Marquis de Bréme upon a single species from 
Mexico. Dinomus was unknown to Lacordaire, who merely reproduced the original 
description; the genus is not represented in any of the large Mexican collections 
before me. 
1. Dinomus perforatus. 
Dinomus perforatus, de Bréme, Rev. Zool. 1842, p. 114°. 
Hab. Mexico}. 
Group HELOPIDES. 
This group already contains about 370 described species; it represents the Group IV., 
the “ Hélopides vrais,” of Lacordaire’s tribe Hélopides. ‘Till the publication of Allard’s 
elaborate monographic revision of the “ Hélopides vrais” (from which several North- 
American as well as many Magellanic or Antarctic species are omitted) the very large 
number of species were principally contained in the genus Helops; the few known 
Tropical-American forms being mostly referred to Nautes and Tarpela. 
Dr. Horn, in his revision of the Tenebrionide of America north of Mexico (Trans. 
Am. Phil. Soc. new ser. xiv. p. 253, and Trans. Am. Ent. Soc. viii. p. 152), places the 
whole of the North-American species in the one genus Helops. 
Allard, however, in his (more recent) revision has divided Helops into a large number 
of genera and subgenera, four or five only of which appear to be represented in the 
New World, by far the greater majority of genera and species being from the north 
temperate zone. . 
From the large number of species (74) now recorded from Central America it will be 
seen that tropical regions also contain a considerable number of ‘ Helopides,’ some of 
which (both apterous and winged) are of brilliant metallic colours; a very large proportion 
of these are described as new. I am unable to identify a single one of our species with 
those of North America, representatives of many of which I have before me for com- 
parison ; we have not, however, any material from the more northern Mexican States, 
and some of the species described from Texas and Arizona may yet be found to extend 
into our region. 
Nautes is here placed at the head of the group on account of its affinity with certain 
“ Cnodalonides.” 
