StaphijUnidai of the Amazon Valley . 365 



Antennffi pitchy, not paler at the base, moderately long ; 

 3rd joint a little longer than 4th ; clnb slender. Palpi 

 pale yellow. Head with the eyes as broad as the elytra, 

 distinctly excavate, and Avith a shining carina at the 

 bottom of the excavation. Thorax rather narrow, but 

 longer than broad, much narrower than the elytra; the 

 sides distinctly rounded in front and narrowed at the base ; 

 the surface densely punctvired, the punctures arranged so 

 as to make the interstices assume somewhat the form of 

 transverse ridges. Elytra rather narrow, quite as long as 

 the thorax, densely and coarsely punctured. Hind body 

 slender, the basal segment rather coarsely jjunctured, 

 carinate in the middle at the base, and finely margined at 

 the sides ; the two following segments more indistinctly 

 carinate in the middle, and more finely punctured ; the 

 segments towards the extremity very finely punctured, and 

 with a very fine, depressed pubescence. Legs slender, 

 rather long, yellowish ; the femora a little darker towards 

 the extremity ; tarsi very slender, 4th joint quite simple. 



In the male the 5th segment of the hind body on the 

 imderside is broadly impressed along the middle before the 

 extremity ; the 6th is still more deeply impressed, and has 

 the edges of the impression a little raised, and furnished 

 towards the extremity Avith a ridge of raised black 

 pubescence ; the 7th segment bears a very long and ex- 

 tremely narroAv notch. 



Tapajos ; a single male. 



Obs. — This species is conspicuous amongst its close 

 allies here described by the dark basal joints of the an- 

 tenna3. 



9. Stenus certatus, n. sp. (Sect. I. A, Er. ) Niger, 

 vix ffinescens, fere opacus, antennis, palpis, pedibusque 

 testaceis, prioribus apice infuscatis ; capite thoraceque 

 dense fortitei'que puuctatis ; abdomine tenuiter margi- 

 nato, crebre, basi sat fortiter, apice obsolete, punctato. 

 Long. Corp. If lin. 



Antennae slender, rather long, yellow, the slender ex- 

 tremity infuscate ; 3rd joint hardly any longer than 4th. 

 Palpi slender, pale yelloAv. Head Avitli the eyes large, 

 very nearly as broad as the elytra, distinctly excaA^ate; at 

 the bottom of the excavation Avith a slightly elcA^ated 

 shining longitudinal space. Thorax longer than broad, a 

 good deal narrower than the elytra, the basal portion dis- 



