534 STAPHYLINID A. 
This genus is established for some small insects allied to Cryptobiwm, but differing in 
the structure of the labrum, mandibles, and tarsi; the structure of the last I look on 
as the most important diagnostic at present. From Scopwodes the genus is distinguished 
by the neck being of the ordinary structure, though narrow. The species at present 
placed in the genus by me belong to three groups, which will probably be found 
ultimately to be valid genera; in the first of these, which forms the type of Ababactus, 
the tooth in the middle of the mandible is deeply bidentate, the antenne are less 
abruptly geniculate, the prosternum is short, and the general facies is as much that 
of Lathrobium or Lithocharis as of Cryptobium; A. gracilis and A. filarius have the 
mandibular tooth undivided, the spines of the labrum minute, the pseudo-terminal 
joint of the maxillary palpi remarkably short and stout, and the prosternum longer 
than in the first group; A. poletus, which forms the third group, has a differently-shaped 
head, strongly geniculate antenne, and the tooth of the mandibles single, and resembles 
Scopeodes in facies. 
I am not acquainted with any species out of our region that I can refer to the genus. 
Mr. Champion informs me that all the species met with by him were found on the 
sandy banks of streams, beneath stones or dead leaves, and chiefly in the forest. 
1. Ababactus depressus. (Tab. XIII. fig. 23.) 
Fusco-piceus ; capite prothoraceque nigricantibus, abdomine piceo-testaceo, antennarum basi apiceque rufis, 
pedibus testaceis; prothorace crebre subtiliter punctato, linea angusta longitudinali levigata; elytris 
elongatis, dense subtiliter punctatis. 
Long. 53 millim. 
Hab. Panama, Volcan de Chiriqui 4000 to 6000 feet, Pefia Blanca 3000 to 4000 feet 
(Champion). 
Antenne elongate, the scape about as long as the three following joints together ; 
joints 3-8 dark, apical joints pallid. Head subquadrate, rather closely and finely 
punctate. Thorax not much longer than broad, curved at the sides. Elytra very much 
longer than the thorax, with close and fine but quite definite punctuation. The male 
has two circular impressions on the fourth ventral plate, and a rather small angular 
notch on the terminal plate. 
The example figured was found on the Volcan de Chiriqui. 
2. Ababactus pennatus. 
Fuscus ; antennis basi apiceque rufis, pedibus testaceis; prothorace obsolete punctato ; elytris quam prothorax 
longioribus, crebrius subtiliter punctatis. 
Long. 43 millim. 
Hab. Panama, Bugaba (Champion). 
Although very similar to A. depressus this is a much smaller insect, and has other 
good distinctive characters; the antenne are less elongate, the penultimate joint being 
