PLATYONYX.—AMERCEDES. 329° 
PLATYONYX. 
Platyonyx, Schénherr, Cure. Disp. Meth. p. 272 (1826) ; Gen. Col. iii. p. 795; Lacordaire, Gen. 
Col. vil. p. 236. 
A monotypic Tropical-American genus nearly related to Centrinus, Odontocorynus, 
and Gereus, though placed (with Leptoschenus*) in a different group of the 
“ Baridiides vrais” by Lacordaire. This author is in error in stating that the fourth 
joint of the anterior tarsi is dilated in both sexes: it is a character peculiar to the 
male, in which sex the three basal joints of the anterior tarsi are also widened, the 
antennal club is elongated, the joints of the funiculus are ciliate within, &c. The 
anterior tibial claw is almost obsolete in both sexes; and the mandibles are straight 
on their inner edge and pointed at the tip. 
The type of Platyonyx, P. ornatus, Boh., is a very conspicuous insect, with a broad 
encircling band of rust-red scales round the sides, base, and apex of the prothorax, 
and a similarly-coloured transverse post-basal fascia on the elytra. 
1. Platyonyx ornatus. (Tab. XVII. figg. 11, lla, 4, 3.) 
3. Platyonyx ornatus, Boh. in Schénh. Gen. Cure, iii. p. 795"; vill, 1, p. 270°. 
2. Leptoschenus gratiosus, Pasc. in litt. 
3. Rostrum stout, closely punctate, the antenne inserted near the apex, the club about as long as joints 
2-7 of the funiculus, which are ciliate within; ventral segments 1 and 2 broadly flattened down the 
middle ; pygidium almost or quite covered by the elytra; anterior tarsi with joints 1-3 ferruginous and 
dilated, joint 4 broadly, subtriangularly widened ; the scales on the under surface of the body white. 
Q. Rostrum abruptly curved and more slender, flattened and dilated towards the tip, closely punctate at the 
base only, and almost smooth thence to the apex, the antennz inserted at the middle, the club about as 
long as joints 5-7 of the funiculus; pygidium exposed at the apex, gradually declivous ; the scales on 
the under surface almost wholly rust-red, similar in colour to those above. 
Hab. tMexico (coll. Pascoe: 2); Panama (coll. Fry: 3 ).—SoutH AMERICA, 
Cayenne !*. 
One female and two males, all contained in the British Museum. 
AMERCEDES. 
Amercedes, Casey, Ann. N. York Acad. Sci. vii. p. 602 (1893). 
Zygobaroides, Pierce, Ent. News, xviil. pp. 382, 384 (Nov. 1907). 
Mandibles (as seen closed) pointed, toothed at the base above; rostrum rather slender, long, almost straight, 
the short basal portion curved and abruptly thickened, at least in the 2, gradually widened in the d 
of A. orthorrhinus ; antennse inserted near the base of the rostrum, joint 1 of the funiculus a little shorter 
than the scape, 2 very elongate, as long as 3-6 united, the club ovate ; prothorax strongly bisinuate at 
the base; scutellum free; elytra subtriangular; pygidium not visible; prosternum very deeply sulcate 
throughout, the ridges extending on to the posterior portion and there becoming very prominent ; 
mesosternum slightly depressed in the middle; femora stout, more or less sulcate along their outer half 
a 
* Leptoschaenus maculatus, Boh., from Cayenne and Brazil, is given as doubtfully Mexican by Lacordaire 
(Gen. Col. vii. p. 238). 
BIOL. CENTR.-AMER., Coleopt., Vol. IV. Pt. 5, September 1908. 20U 
