StapliylinidcB of the Amazon Valley. 371 



four basal segments rather coarsely and closely, but not 

 densely punctured ; almost without pubescence. The 

 punctuation of the metastemvira coarse. 



Para ; a single female, collected by Mr. Smith. 



Ohs. — Though this species is closely allied to S. genalis, 

 it is undoubtedly quite distinct, the sculpture being con- 

 siderably coarser and more sparing. 



16. Stenus nigricans, n. sp. (Sect. II. B, Er.) Elonga- 

 tus, angustus, niger, nitidus, antennis, palpis, pedibusque 

 flavis ; "prothorace subcylindrico, dense punctato ; elytris 

 thoracis longitudine, crebre fortiter punctatis ; abdomine 

 fortiter crebre punctato. Long. corp. 2^ lin. 



Antenna3 yellow, long and slender, the three apical 

 joints distinctly incrassate. Palpi elongate, yellow. Head 

 even broader than the elytra, the space between the eyes 

 a little depressed, almost flat, the middle being very obso- 

 letely elevated; it is black and shining, moderately coarsely 

 and not densely punctured. Thorax a good deal nar- 

 rower than the elytra, much longer than broad, distinctly 

 rounded at the sides, so that it is slightly narrowed both 

 in front and behind ; it is covered with a dense, rather 

 coarse, almost rugose punctuation. Eh^tra scarcely so 

 long as the thorax, narrow, the shoulders not very pro- 

 minent ; they are black and shining, coarsely punctured, 

 the punctuation at the base dense, more sparing at the 

 apex ; at the extreme base is some delicate white pubes- 

 cence. Hind body cylindric, slender, only the basal 

 segment margined, the four basal segments rather coarsely 

 punctured, and with a white pubescence at the extreme 

 base of each. Legs clear yellow. 



The male has a broad and deep excision on the ventral 

 plate of the 7th segment of the hind body ; the 6th seg- 

 ment is a little depressed near the hind_ margin, and 

 there finely punctured, the hind margin being distinctly 

 emarginate. 



Pant; two individuals {$ and ? ), collected by Mr. 



Smith. 



Qjjs. — This species bears a great resemblance to «S'. ex- 

 cisus and ^S'. Parce ; but it is more slender than S. excisus, 

 and has the elytra more closely punctured, and the punc- 

 tuation of the hind body considerably coarser. It is rather 

 smaller than S. Pares, is blacker, and more finely punc- 

 tured, and has the pubescence at the base of the abdominal 

 segments distinct. 



B B 2 



