Coleopterological Notices, V. 491 



Ctenistini. 

 BIOTIJS 



Could Dr. Brendel have had before him a representative of the 

 European Chennium, I am sure that he would not have united that 

 remarkable genus with Atinus and Biotus in his recent monographic 

 study of the Pselaphidae ; the differences are manifold and very im- 

 portant ; they may be expressed as follows : — 



Middle coxse distinctly separated by the wide sternal processes ; sides of the 

 clypeus conically and acutely prominent ; mentum transverse, longitudi- 

 nally convex and coarsely setulose ; maxillary palpi with the last two joints 

 large, distinct and covered with short recumbent squamiform setae. 



Chennium 

 Middle coxse contiguous, their cavities broadly confluent ; sides of the clypeus 

 normal ; mentum much more deeply seated, flat and subglabrous ; max- 

 illary palpi much smaller, with the last two joints apparently combined 

 in one. 

 Labial palpi invisible ; muzzle below the antennae greatly extended beyond 

 the eyes ; antennae cylindrical, nearly as in Chennium but with the 

 second joint small ; posterior tibiae compressed throughout, rather nar- 

 rower toward apex IBiotlls 



Labial palpi robust and distinct : muzzle not produced; antennae slender. 

 normal, moniliform, gradually and strongly thickened toward apex ; 

 posterior tibiae clavate at apex AtinUS 



In Biotus it is almost impossible to make out the true structure 

 of the maxillary palpi without dissection. The entire organ is less 

 than one-third as large as in Chennium, and all that can be clearly 

 seen is a single oval truncate joint, which is robust, longer than 

 wide, apparently flattened beneath and covered sparsely with 

 minute recumbent hairs; there is quite certainly a small basal 

 joint, and, apparently, a minute wart-like tubercle on the outer 

 side of the second joint. 



In the two species of Atinus the palpus differs surprisingly in 

 size and form. In monilicornis it is very minute, scarcely larger 

 than in Biotus, the second joint stout, sublunate, with the oblique 

 pointed apex apparently setulose, while in brevicornis it is nearly 

 twice as large, not lunate but somewhat spindle-form, gradually 

 and finely produced beneath and bearing at apex a short appen- 

 dage. In both of these species the organ is sparsely clothed with 



