210 RHYNCHOPHORA. 
and more slender than X. commizxtus, with no perceptible narrowing of the prothorax 
in front, with the elytra somewhat narrowed behind, the declivity quite convex, the 
sutural stria not impressed, and the interstices not elevated; moreover, the absence of 
the coarse punctures on the head at once distinguishes it. 
21. Xyleborus posticus. 
Xyleborus posticus, Eichh. Berl. ent. Zeitschr. 1868, p. 281’; Rat. Tom. p. 353°. 
Hab. Mexico”, Toxpam (Sallé), Almolonga (Hoge); GuatemaLa, Senahu, Chiacam, 
and San Juan in Vera Paz, Cerro Zunil, San Lucas Toliman, Guatemala city, Capetillo 
(Champion); Panama, Volcan de Chiriqui (Champion)—VENEZUELA!?; Brazit, Tejuca 
(Clark). 
One of the commonest Xylebori in Tropical America. Resembling in general 
appearance the members of the group which includes X. torquatus and X. affinis, it can 
be distinguished from them at once by the subquadrate prothorax. 
22. Xyleborus costaricensis, sp. n. 
Fem. Elongata, subcylindrica, sat nitida, picea, parce fusco-pilosa; prothorace oblongo, apice rotundato, dorso 
medio umbonato, posterius parce punctato; elytris lineato-punctatis, interstitiis planis punctis raris 
piliferis notatis; declivitate valde obliqua, ad apicem subimpressa, infra marginata, subopaca, interstitiis 
equaliter minute tuberculatis. 
Long. 3°5 millim. 
Female. Elongate, subeylindric, piceous, with thin fuscous pubescence. Front subelevated over the mouth, — 
the elevation and a median space dull and impunctate, the sides with close deep piliferous punctures ; 
eyes rather broad, with a narrow deep emargination ; antennz fusco-testaceous. Prothorax longer than 
broad, the hind border curved, its angles rounded, the sides slightly curved and not narrowed to the 
anterior third, the apex rounded; surface umbonate about the middle, the elevation not very transverse, 
asperate in front, with erect pubescence, somewhat shining behind, with a few irregularly disposed fine 
punctures. Scutellum obtuse triangular, shining, black. Elytra as wide as the prothorax and fully one- 
half longer, their base truncate, the shoulders rounded rectangular, their calli obsolete, the sides nearly 
parallel to the apical third, with very slight posterior amplification, thence gently curved and narrowed to 
the circularly-rounded apex; surface piceous-brown, subconvex from the base, becoming very obliquely 
and gradually declivous behind the middle, shining, with rows of rather remote, shallow punctures, 
interstices flat, subrugose, with remote piliferous punctures; declivity duller, flattened posteriorly, 
subimpressed near the acutely-margined apex on each side of the suture, the punctures of the strize 
shining, the interstices with regular series of minute piliferous tubercles, the hairs fine and short. 
Underside piceous, subglabrous, the abdomen impunctate. Legs fuscous, the anterior tibie rather 
strongly dilated, with the superior border subangulate. 
Hab. Costa Rica, Volcan de Irazu (Rogers). 
One example. In the structure of its elytra, but not of its prothorax, this species 
appreaches those of Eichhoff’s group +-+, and occupies a somewhat intermediate 
position between it and group ++ -+-+, which consists of species in which the prothorax 
is cylindric, with a strongly rounded apical border. 
