OF THE EASTERN WORLD. 
133 
for the establishment of generic and sub-generic groups, nearly 
every species would form a different group. And yet there is no 
other character which will separate Diceros (or Dicheros, as Gory 
and Perckeron write the word) from the other Heterorhinm. 
In addition to the Asiatic species of this group subsequently 
noticed, the group comprises the African species C. Africana, 
Drury , C. stigma, Pal Beauv ., and C. suturalis *, as well as C. 
smaragdina and chloris of Gory and 'Percheron’s Monograph; 
which last two species appear to be also African insects, judging, 
at least, from the specimens in Mr. Hope’s collection, ticketed by 
M. Gory himself. 
A rigid investigation of the species of this group, has shown the 
relative value of the different characters employed in their classifi¬ 
cation. The form of the head varies almost in every species ; the 
maxilla? are sometimes terminated by a simple and sometimes a bifid 
lobe, this difference sometimes occurring in the same individual; 
and when simple, itvaries very considerably in form in the different 
species. The form of the mesosternal process is variable, but gene¬ 
rally very much elongated and acute ; in IT. Hopei and Bengalensis 
it is, however, short and obtuse. There is considerable dif¬ 
ference in the amount of emargination of the anterior margin of 
the mentum; the club of the antennse is also slightly variable in 
size in the opposite sexes of some of the species. There is 
also considerable difference in the spur at the middle of the four 
posterior tibiae; indeed, in some species it is quite obsolete. 
The apex of the elytra is sometimes rounded, and sometimes pro¬ 
duced into two acute spines at the suture, and the unguiculi differ 
very much in size. The form of the body and the colouring of the 
species also differ materially. All these variations will, however, 
be more particularly noticed under each species. 
Species I .—Heterorhina nigritarsis. (Plate 30, fig. 7, 7 a and b, and 8 a, b, c, d.) 
Cetonia n . Hope, Syn. Col. Nep. in Gray’s Zool. Misc. 1. 24. Gnalhocera n. Gory 
and Percheron, pi. 20, fig. 3. 
This species bas all tlie legs as well as the clava of the antenna considerably elongated in 
the male, •which is tho only sex 1 have seen, so that I am uncertain whether a corresponding 
elongation exists in the opposite sex. The clypeus (fig. 8 d) is produced in front into a 
conical, somewhat recurved plate truncated in the front. The crown of the head is slightly 
keeled down the centre. The fore feet are quite simple, as are also the middle tibiae, but the 
hind ones are slightly spurred below the middle. The abdomen in this sex is not channeled 
beneath. The mesosternal process is (fig. 7 a and 76) rather long, pointed, and nearly straight. 
The mandibles (fig. 8 a) are rather small, with the horny blade rather longer than the square 
membranous part; the maxilla* (fig. 8 6) are considerably elongated, tlie inner lobe produced 
into a straight obtuse point, and the upper lobe large, and extending far beyond the front of 
* 1 have not examined C. Feisthamel, viridi-cyanea, and monocoros. 
