PLATH XX 
THE COLEOPTEROUS GENUS HYPOCEPHALUS ILLUSTRATED. 
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Tue genus Hypocephalus was first proposed by M. Desmarest, 
in Guerin’s “ Magasin de Zoologie” for 1832 (vol. 1, pl. 24), being 
founded upon a most anomalous beetle of large size from the 
province of the mines in the interior of Brazil, whose natural rela- 
tions have perplexed all subsequent entomologists. The insect is 
described in detail, and outline figures are given of the dorsal and 
lateral aspect of the insect, with a front and side view of the head 
and figures of the palpi detached. My figure 2 is copied from 
Desmarest’s figure of his insect seen from above. 
Five years afterwards, Gist], a German entomologist, unac- 
quainted with Desmarest’s figure, published another description 
and figure of evidently the same insect, in the first number of 
his “‘ Faunus,” under the name of Mesoclastus paradoxus, forming 
it into a new and distinct family of the Pentamerous Coleoptera, 
named Xenomorphze. The upper and under sides of the insect 
and the front of the head are represented; my figure 3 being 
copied from his first figure. 
For the insect represented in my figure 1, I have to return my 
best thanks to A. Melly, Esq. who has thus enabled me to dissect 
this singular insect, and give a correct description of the parts of 
its mouth. Notwithstanding the differences observable in the 
three figures, I consider that they are all representations of the 
same insect; perhaps a variation in the sex of M. Desmarest’s 
imsect may account for the great difference between his and the 
other two figures. 
The insect exhibits, as M. Desmarest well observes, a certain 
analogy with the mole cricket in the large size of the prothorax, 
thick hind legs and short antennz. The large size of the hind 
feet, and especially of the posterior coxee, have rendered necessary 
an extra-development of the mesosternum, which is pushed so far 
backwards that the abdomen is reduced to a very small size. The 
head is of a curious form, its lateral posterior angles being extended 
backwards, forming somewhat acute and prominent points; on each 
side beneath the antenne the head is produced into a conical 
D 2 
