410 PROCEEDINGS OF THE ACADEMY OF [1899. 



lum distinctly impressed; ventral abdominal segments without 

 appendages. Length 19-21 mm. 



Chapada, March, October, December. Seven $, two d" speci- 

 mens. Striatifrons comes closer to chalybeus than to ccendeopennis 

 and recurvirostris, both of which have the clypeus rounded at sides, 

 and their c? abdomen is provided with leaf-like appendages beneath. 



Zethus chalybeus Sauss. 

 Chapada, April; Santarem. Four ? specimens. 



Zethus sessilis n. sp. 



Black; abdomen with a grayish pile; mandibles medially, spot 

 on tegulte, legs more or less, and sides of petiole dark reddish or 

 reddish brown; wings fuscous as far as stigma, darkest in costal 

 cell, otherwise clear. 



9. — Head with strong even punctures not close, the front with 

 some rugae in addition; clypeus longitudinally rugose or rugoso- 

 punctate, subrounded at sides, about one-third broader than long, 

 truncate anteriorly and with two widely separated teeth ; space 

 between hind ocelli equal to more than half that between them 

 and eyes; scape shining, in length equal to the pedicel and follow- 

 ing four joints united; pronotum very sharply and highly margined 

 or crested, but scarcely dentate; dorsulum coarsely punctured with 

 an impressed line anteriorly in middle, and four feebler ones pos- 

 teriorly, the two medial impressions strongest and farther apart 

 than they are from the exterior ones; scutellum subconvex, im- 

 pressed ; postscutellum entire ; middle segment rugose except medi- 

 ally, Avhere it is concave or broadly depressed and like the sides 

 finely punctured, a faint trace of a carina between the upper sur- 

 face aud sides ; swollen portion of petiole short, campanulate, with 

 dense shallow punctures, the basal stem longer than hind coxoe; 

 second segment practically sessile with first, the pedicel being 

 exceeding short ; dorsal surface of abdomen with a fine dense punc- 

 tuation, that on ventral surface quite as fine, but not so dense. 

 Length 13-14 ram. 



cJ*. — Head not or scarcely striated as in ?, coarsely punc- 

 tured; clypeal teeth stronger; space between hind ocelli less; apical 

 antennal joint exceedingly minute, not one -third the size of the 

 preceding one, and so placed as to form a small hook. Length 

 13-14 mm. 



