232 MR. CURTIS ON HYPOCEPHALUS, A GENUS OF COLEOPTERA. 
the basal joint beneath: middle pair almost as long as the tibiæ, basal joint equal in length to the 
three following, clavate, 2nd and 3rd somewhat obovate, 4th the smallest, obtrigonate, all truncated, 
concave beneath, with a spine at each angle, basal joint with 2 series of hairs beneath, 5th joint 
elongate, clavate, produced into a semicircular horny plate on the underside: hinder pair with the 
basal joint much shorter than that of the middle pair; claws not large but curved and acute. 
Fam. XENOMORPHÆ, Gistl. Mesoclatus paradoxus, Gistl. 
HYPOCEPHALUS ARMATUS, Desmarest?  Pitchy: head and mandibles with scattered punc- 
tures: palpi and antennæ castaneous. Thorax black, with faint scattered punctures, 
stronger round the margins: scutel with the base densely punctured, and opake black, 
apex punctured but shining, and forming a smooth line to the base. Tibiæ punc- 
tured, especially above, the hinder rugose ; tarsi castaneous ; claws black ; apex of coxæ 
and trochanters inclining to castaneous. Abdomen with an ochreous membranous line 
at the base of each segment. It is 2} inches long* ; the thorax about 10 lines broad. 
There are so many differences between M. Desmarest’s figure and Mr. Turner’s speci- 
ment, that in all probability they are, if not distinct, the sexes, this being a male I pre- 
sume. My descriptions and figures may assist in settling this question, and I trust they 
will prove serviceable in illustrating the history of this anomalous beetle, as well as lead 
to a careful examination, in living specimens, of the extraordinary apparatus under the 
head, which may also be a sexual character. 3 
Before further discussing the position of Hypocephalus I will attempt to complete its 
history as far as I am able, but at present I can only conjecture its habits by analogy. 
Many specimens of this beetle have been found in the mining districts of Brazil, con- 
siderably south of the Equator. Three are reported to have been met with in the carcase 
of a dead horse, and others creeping upon the ground. It is also stated to live in rotten 
wood in forests. There is every reason to believe that Hypocephalus is a burrowing insect, 
and probably lives underground. Its attenuated form is admirably adapted to forcing its 
wedge-shaped head into any crevice, with an incredible power of resistance in the hind 
legs, and its tapering behind is no less calculated to enable it to retreat, folding its enor- 
mous limbs by the sides of its small body. Under such circumstances one would expect 
to find unusually small antennæ, which readily fall back and beneath the head, for pro- 
tection. Wings of course are useless, whilst its connate or soldered elytra give additional 
solidity to the body, and their partial separation allows of an expansion of the abdomen, 
under great exertion or pressure. 
The fore feet, like those of other burrowing insects, are fitted for scraping, clearing 
away the refuse, and passing it backward. The lobed jaws probably fit into the wonderful 
apparatus at the base of the head, and together with the protuberances on either side seem 
to form an instrument for grinding its food, which may then be deposited until required 
in the pouch, which looks indeed like a ruminating stomach. The mandibles are formed 
for clawing and pulling, or tearing, and the two rows of teeth, like the molars of an ele- 
* Mr. Westwood’s specimen is 3} inches long. 
+ This example had broken feet, as my figure shows, and probably it was aged, or dead when found; young and 
perfect specimens may have longer and sharper spines and more hairs upon the limbs. 
