3U8 ]\ii-. D. Slmrp's Cnntrihntwni> to the 



tooth or tubercle on the inside ; the ventral plate of the 

 7th segment has a rather large notch, the 6th is flattened 

 along the middle, and finely but sparingly pubescent on 

 the flat part, and has the hind margin a little emarginate. 

 Rio Purus ; a single male, captured by Dr. Trail on the 

 25 th October, 1874. 



12. Stcnus ventralis, n. sp, (Sect. II. B, Er.) Elon- 

 gatus, plumbeo-niger, sat nitidus, albido-pubesceus, an- 

 tennis, palpis, pedibusque pallide flavis ; thorace elytris- 

 que crebre fortiter punctatis, his thoracis longitudine ; 

 abdomiue parcius subtiliter punctato. Long, coi'p. 2^ lin. 



Antenna? pale yellow, elongate and slender, longer than 

 head and thorax; 3rd joint more than twice as long as 2nd, 

 and a good deal longer than 4th ; joints of the club elon- 

 gate and slender. Palpi pale yellow, elongate. Head 

 fully as broad as the el}tra, slightly depressed between the 

 eyes, the central part very indistinctly elevated ; the punc- 

 tuation moderately fine, not dense, rather more sparing 

 about the middle. Thorax a good deal longer than broad, 

 subcylindric, but distinctly broader in the middle than at 

 the extremities; the surface closely and rather coarsely 

 punctured. Elytra just about as long as the thorax, but 

 a good deal broader ; the shoulders distinct, the sides 

 slightly curved ; the punctuation rather coarse, a little 

 coarser than on the thorax, rather close. Hind body 

 elongate and cylindrical, the basal segment finely mar- 

 gined, each segment with a long Avhite pubescence, Avhich 

 is most distinct on its basal portion ; the basal segments 

 finely but distinctly, rather sparingly pimctured, the apical 

 ones quite finely and sparingly. Legs pale yclloAv, elon- 

 gate, rather slender, the lobes of the tarsi broad. 



In the male, on the underside, the 7tli segment of the 

 hind body bears a deep, narrow notch; the 6th is more 

 closely punctured and pubescent along the middle than at 

 the sides; the 5th is depressed along the middle before the 

 apex, the depression impunctate but scarcely shining; the 

 4th and 3rd have similar but not such deep depressions, 

 while the basal one is smooth and shining in the middle 

 at the extremity. 



Tapajos ; one male, one female. 



13. Stenus extensus, n. sp. (Sect. II. B, Er.) Elon- 

 gatus, plumbeo-niger, sat nitidus, albido-pubescens, anten- 



