RHEXIUS.—EURHEXIUS. 4] 
constricted so as to form a short tube in which the head is inserted by a very short 
neck ; this thoracic tube has the appearance of being only a development, rather greater 
than usual, of the neck of the head, but it is not so. 
1. Rhexius optatus. (Tab. I. fig. 23.) 
Testaceo-castaneus, subtiliter pubescens ; capite fortiter impresso, vertice emarginato ; prothorace anterius 
abruptissime constricto, parte anteriore sat elongato ; abdomine parum elongato. 
Long. vix 11 millim. 
Hab. Panama, Volcan de Chiriqui 4000 to 6000 feet ( Champion). 
Antenne strongly elbowed; the ninth joint rather large, not strongly transverse. 
Head very short, the vertex conspicuously concave-curvate behind. Thorax with the 
anterior constriction very abrupt and rather elongate, so as to be as long as broad. 
This is extremely closely allied to the typical species, £. insculptus, Lec., from 
Louisiana, so that at first I thought they were identical. R. optatus is, however, a 
little smaller, has the ninth joint of the antennz larger, the head shorter, the peculiar 
peduncle of the front of the thorax longer, and the hind body less elongate. Only one 
example was obtained. 
EURHEXIUS. 
Corpus subdepressum. Antenne rect; ad basin distantes, clava tri-articulata. Caput breve transversum, 
collo abrupto, subtus pubescens. Palpi maxillares parvi, articulo ultimo ovali. Coxe anteriores elongate, 
prominulx, lineares. Coxe posteriores contigue. Tarsi breviusculi, unguiculis duobus inequalibus 
prediti. Abdomen marginatum. 
This genus differs from Rhewius, to which it is closely allied, by the ungeniculate 
antenne, and the comparatively normal condition of the prothorax ; this latter, though 
with the anterior part more or less narrowed and prolonged according to the species, 
never exhibiting the peculiar structure seen in Rhexius. The basal joint of the antenne 
varies in length according to the species, but though it is sometimes unusually long 
the antenne are not geniculate. Hurhewius is probably peculiar to Tropical America, 
and no doubt Lhexius simonis and R. procerus, Reitter, belong to it. 
1. Kurhexius vestitus. (Tab. I. fig. 22.) 
Rufo-brunneus, densius pubescens, haud nitidus; capite brevi, anterius curvatim depresso, vertice longitudin- 
aliter impresso ; prothorace minus elongato, canaliculato, ante basin sulcato ; elytris humeris subelevatis, 
basi sex-foveolata. 
Long. 23 millim. 
Hab. Panama, Volcan de Chiriqui 2000 to 3000 feet (Champion). 
Antenne rather stout; the basal joint moderately long, but not reaching so far out- 
wards as the convexity of the eye ; the second joint rather small ; joints 3-8 still smaller, 
similar to one another, the ninth and tenth larger, transversely subquadrate; the ter- 
minal joint as long as the preceding two together, very pubescent, Head very broad, 
BIOL. CENTR.-AMER., Coleopt., Vol. II. Pt. 1, April 1887. G* 
