210 MALACODERMATA. 
Fam, BOSTRYCHIDZ. 
The Bostrychide are a family of small extent, clearly related in many of their details 
to both the Cleride and the Anobiides. They are, as far as is known, xylophagous; 
and we meet with here a curious modification of the apical portion of the elytra, for 
the purpose of ejecting the comminuted fragments of wood from their bores, which is 
so obviously analogous to that in the Scolytidé as to be frequently mistaken for a case 
of real affinity. The distribution of the smaller species is nearly universal; but it is in 
tropical Africa that the most highly developed types occur, in the genus Apate. ‘The 
New World, however, shows a very considerable contingent, both in number of species 
and their size. 
Subfam. BOSTRYCHINT. 
POLYCAON. 
Polycaon, Castelnau, in Silberm. Rev. Ent. iv. p. 30 (1836). 
About ten species of this genus are known. ‘The typical species is a Chilian insect ; 
one is described from Demerara; the remainder are peculiar to the northern continent 
of America. 
1. Polycaon exesus. (Tab. X. figg. 189,196.) 
Polycaon exesus, Leconte, Proc. Ac. Phil. 1858, p. 74; Horn, Revision, Proc. Am. Phil. Soc. 1878, 
p-. 553°. 
Hab. Norru America, peninsula of Lower California !.—MeExico, Cordova (Sallé, ¢ ) ; 
GuATEMALA, Torola( 3 2 ), San Gerénimo (Champion, @ ). 
The description of the female, which was the only sex known to Leconte and Horn, 
perfectly agrees with our insect. I feel no doubt in uniting the males in Sallé’s and 
Champion’s collections with this, especially as the latter collector met with both sexes 
at Torola: the specimens figured in our Plate are both from the latter locality. The 
largest specimen (one from Cordova) is 21 millim. in length; the head is finely and 
closely granulate all over; the thorax thickly punctured on the disk with a fine 
impressed central line; the elytra nearly glabrous, their apex obliquely declivous, the 
margining carina extending so far as to form scarcely more than a semicircle; at the 
top of the declivity near the suture a longitudinal subdentiform callus. The smaller 
male (also from Cordova) is 12 millim. long; it agrees with the larger one, excepting 
that the thorax is more compressed laterally, the elytra have a few coarse punctures at 
their bases, and the suture more evidently raised at the apex. The male from Torola 
is intermediate in size, but is clearly of the same species. I possess males which I 
