272 RHYNCHOPHORA. 
side ; disc blackish-pitchy, ferruginous-yellow at the sides, declivous and convex before the middle and 
asperate, behind cylindrico-convex, moderately shining and distinctly though not strongly punctured. 
Scutellum rather large, rounded-triangular, subrugose. Elytra scarcely as wide as the prothorax, and 
about one-third longer, subtruncate at base, nearly parallel-sided to the middle, thence slightly narrowed, 
the apical borders separately rounded externally and rather narrowly emarginate; surface deep piceous, 
a little lighter at the shoulders, cylindrical before the declivity, glabrous and rather shining, very finely 
punctured in rows and subrugulose; declivity obliquely excavate, beginning almost at the middle, 
obcordate, its fundus flat, shining, with a few scattered points and piliferous tubercles, its margins well- 
defined throughout, bearing on each side three small pointed tubercles at the upper part, a broad obliquely 
trancate tooth about the middle, and a longer clubbed tooth below. Underside ferrugino-testaceous ; 
extremity of the abdomen black. Legs testaceous, the knees darker ; anterior tibia with strong blunt 
serrations, 
Hab. Mrxico? (Mus. Vind. Ces.). 
The only specimen that I have seen is the type described by Ferrari!. In his descrip- 
tion he associates as sexes two distinct forms—one from Mexico (his ¢), the other 
from Venezuela (his 2). The latter (Bostrichus quadrituberculatus, Moritz, in litt.) 
belongs to the group of species in which the elytral declivity is impressed along the 
suture, convex and bituberculate, but not margined on either side; it has no fringe 
to the antennal club. The difference between the two forms in the structure of the 
elytra is not sexual, for it is in kind and not in degree. Ferrari’s name being retained 
for the Mexican form, that from Venezuela may be conveniently known as Pterocyclon 
quadrituberculatum, nom. n. [=Corthylus validus (2 nec 3 ), Ferr.]. 
The type-specimen of P. validum has lost the club of both antenne, and I cannot 
refer it to either sex; it bears no locality-label, but in Ferrari’s work (p. 61, note 2) 
this particular example is stated to be Mexican. 
2. Pterocyclon melanura, sp. n. (Tab. VIII. figg. 18, ¢ ; 13a, apex of 
elytra, 3.) 
Mas. Cylindricus, elongatus, nitidus, ferrugineus, fronte, prothoracis.macula subapicali et elytris post medium 
nigricantibus, antennis pedibusque infuscatis; prothorace oblongo postice levi; elytris indistincte 
lineato-punctatis, ad apicem oblique excayatis, ambitu acuto in utroque elytro bispinato infra marginato. 
Long. 4:2 millim. 
Male. Cylindric, elongate, shining. Forehead subconvex, blackish, dull, subimpunctate, the mouth thinly 
fringed ; antennw piceous-brown, the club broad-oval, with nearly transverse sutures, the second sinuate. 
Prothorax fully one-third longer than broad, parallel-sided, circularly rounded at apex, the base 
subtruncate with rather obtusely-rounded hind angles; surface without discal elevation, ferruginous, the 
anterior third gradually declivous and convex, with an infuscate median patch, and asperate with rather 
weak transverse imbricate elevations, the posterior part smooth, with scattered microscopic punctures. 
Scutellum small, rounded. Elytra one-fourth longer than the prothorax and scarcely so wide at the base, 
parallel-sided, with rounded humeral angles; surface cylindric, ferruginous, gradually becoming black 
towards the apex, with irregular rows of microscopic punctures ; apex obliquely truncate, excavate, ob- 
cordate, the margins divergent above, and armed on each side with an acute conical spine near the suture, 
below which the margin is produced obliquely in a curve to form the upper border of a longer horizontal 
incurved tooth, below which the margin becomes nearly vertical, strongly elevated, and inflexed beyond 
the apex of the suture in a rounded angle, forming with its fellow a triangular emargination ; fundus of 
the excavation concave on each side, subconvex longitudinally along the suture. Underside and legs 
pitchy-brown ; anterior tibie rather strongly spinous, 
