3G2 Mr. D. Sharp's Contributions to the 



along the middle and finely pubescent, the hind marghi 

 slightly emarginate ; the 7th segment has a very elongate 

 and narrow notch. 



Tapajos ; two males. 



Obs. — This species bears an extreme resemblance to 

 S. tlnctus, but is more slender ; it is more shining, has 

 the punctures on the elytra rather less crowded, so that 

 the interstices are more shining, and the limbs are still 

 shorter. 



5. Stenus vacillator, n. sp. iEneo-niger, subnitidus, 

 palpis flavis, antennis fliscis, basi cum pedibus testaceis ; 

 li"untc bisulcata et angustc carinata ; thorace fortiter trans- 

 versim rugOKSO-punctato ; elytris fortiter punctatis, inter- 

 stitiis nitidulis. Long, corji. fere 2 lin. 



Antennfe dusky yellow, infuscate towards the extremity, 

 short; 10th joint about as long as broad. Head nearly 

 as broad as the elytra, densely punctured, distinctly ex- 

 cavate, and with a very fine but distinct shining carina 

 along the middle. Thorax rather longer than broad, dis- 

 tinctly rounded at the sides, deeply transversely rugose, 

 the interstices narrow. Elytra about as long as the 

 thorax, rather coarsely and closely punctured, the inter- 

 stices wider on a space near the suture than elsewhere. 

 Hind body rather closely punctured, the basal segment 

 distinctly, the apical ones obsoletely ; the basal segment 

 very finely carinated in the middle, the following two only 

 veiy obsoletely carinate. 



Tapajos ; a single female. 



Obs. — I have some doubts whether the individual above 

 described be really distinct from S. cognatus. It is just 

 the same size as that species, but has the antenna3 a little 

 shorter, the vertex more finely carinate, the interstices of 

 the sculptm'e on the thorax and elytra rather narrower, 

 and the carina} of the basal segments of the hind body less 

 distinct. These difierences, however, are but slight, and 

 it is possible may be sexual or indi\adual rather than 

 specific characters. I have, however, another female fi-om 

 St. Paulo which agrees in these respects with the aS". vacil- 

 Idtor, and is probably conspecific with it ; but as it departs 

 very slightly in one or two other respects fi-om the Tapajos 

 individual, I have drawn my description entirely from the 

 latter. 



6. Stenus cursitor, n. sp. Gracilis, teneo-niger, niti- 



