STENUS. 663 
54. Stenus chiriquensis. 
Gracilior, niger, vix perspicue metallescens, nitidus ; antennis, palpis pedibusque flavis; capite fere plano; 
prothorace cylindrico, densissime punctato, fere rugoso; elytris humeris rectis, densissime punctatis ; 
abdomine segmentis duobus ultimis impunctatis. 
Long. 54 millim. 
Hab. Panama, David in Chiriqui (Champion). 
This is one of the most slender species, and greatly resembles S. placidus and 
S. albipes, but may be distinguished from both by the terminal two (before the arma- 
ture) abdominal segments being quite without punctures; it has, moreover, the punc- 
tuation of the thorax and elytra denser, and the shoulders of the latter more prominent ; 
it is one of the most densely punctured Stent. One female. 
55. Stenus cylindricus. 
Gracilior, niger, nitidus ; antennis, palpis pedibusque flavis; capite leviter excavato, medio parce punctato; 
prothorace elongato, angusto, cylindrico, fortiter punctato; elytris prothoracis longitudine, fortius 
punctatis ; abdominis apice fere impunctato. 
Long. 6 millim. — 
Hab. Mexico (coll. Chevrolat), Cordova, Jalapa (Hége) ; British Honpuras, R. Hondo 
(Blancaneaux); Guatemaua, Zapote, San Gerdnimo, Purula, Chiacam (Champion) ; 
Nicaracua, Chontales (Janson); Panama, Volcan de Chiriqui 2000 to 3000 feet 
(Champion). 
This species is closely allied to S. godmani, but the male characters are different ; it 
may also be readily distinguished from that species by the antenne being less elongate, 
with avery much shorter club, the head smaller and the vertex flatter, the thorax 
narrower and more cylindric, and the latter and the elytraless densely punctate. In the 
male the segment of the armature is only about half as large as it is in S. godmani, and 
its ventral plate is not emarginate at the tip; the terminal segment has an elongate 
narrow excision; the preceding segment is emarginate at the tip, depressed along the 
middle, and there covered with very dense and minute pallid pubescence. 
We have received a small series from Mexico and also from British Honduras, and 
these specimens agree well; but from the more southern localities the unique expo- 
nents are, without exception, females, and as they all differ, more or less, from the 
Mexican series, it is possible they may not all belong to this species. 
56. Stenus placidus. 
Angustior, elongatus, nigerrimus, nitidus ; antennis, palpis pedibusque pallide flavis; capite leviter excavato, 
disco parcius punctato; prothorace elytrisque fortiter punctatis, his angustis ; abdomine fortiter punctato. 
Long. 53 millim. 
Hab. Panama, Pefia Blanca 3000 to 4000 feet (Champion). 
In this species the male has the ventral plate of the armature with a small shallow 
