CXI 
The chief peculiarities of Jypocephalus are 1, the antennæ, 2 
the peculiar cephalothoracic space, 3 the enormous and peculiar 
hind legs, and 4, the five-jointed tarsi. 
As regards 1, the antennæ, it is to be remarked that there pre- 
vails in the Longicorns extreme variety in these organs ; and the 
structure of the antennæ of such a Prionid as Polyarthron barba- 
rum is for more different from that of the average Prionidæ, than 
the simple structure of antenna of Hypocephalus is from the also 
very simple structure of the same part seen in Dorysthenes mon- 
lanus ©. 
2. The cephalothoracic space is certainly only a peculiar deve- 
lopment and extension of the membrane connecting the head 
and thorax in the Coleoptera generally, and though of great 
interest from its unknown function, can give its possessor no 
claim to great isolation. What the fonction of this space may be it 
would be useless to speculate on. It is probable that the membrane 
covering it is an organ of sensation in its posterior portion, and it 
is quite possible it may prove to have a sexual origin. The whole 
anterior margin of the prosternum is thickened and divided into 
a number of pits, and the large middle notch is very setose, and if 
it should prove that this space has a sexual sensitiveness, it would 
explain how it is that the males sture (as I suppose) to wound one 
another in this space. 
3. The peculiar hind legs are quite insufficient to justify the isola- 
tion of this insect as a distinct family of Coleoptera. (I use here the 
ordinary language of classificis in order not to bring additional 
ideas into this particular discussion.) If it were so, we must make 
Sagra à family, or the Afeuchides, or numerous other Coleoptera. 
Moreover the character is to a great extent merely sexual. 
4. The five jointed tarsi. These are undoubtedly the greater 
peculiarity of Hypocephalus as a Longicorn ; nevertheless it must 
be observed that in the tetramerous Coleoptera of various divi- 
sions there exist anomalous members with five jointed tarsi. 
Cf. Dryophlhorus in Curculionidæ, Polyoptilus in Phylophaga, 
and Parandra and Dorysthenes in Longicorns. And in view ofthe 
point under discussion, the latter example seems to be conclusive. 
There exists in Dorysthenes at the apex of the third joint ofthe 
tarsus, not merely an exposed basal knot, but a true articulated, 
though minute, joint intervening between the third and the fifth 
joints, and it is only in the greater development of this joint that 
Hypocephalus differs, as regards the tarsal structure from Dory- 
sthenes. 
It is quite clear to me therefore that Hypocephalus should be 
placed as a separate member of the Prionidæ on account of its 
