1899,] NATURAL SCIENCES OF PHILADELPHIA. 485 



divides the bases of antennae and extends slightly on the clypeus; 

 flagellum clavate, the first joint about as long as the two following 

 united ; space between hind ocelli less than that between them and 

 eyes; pronotuni cristate, rather square anteriorly in consequence 

 of the strongly augulate sides; dorsulum longitudinally rugoso- 

 striate, with two longitudinal raised lines or swellings medially, 

 anteriorly in the middle with a fine raised line, and with a pol- 

 ished tubercle at each side close to the tegula ; scutellum broadly 

 sulcate down middle, on each side of which it is polished; post- 

 scutellum broadly and angularly emarginate; middle segment 

 rugose, but rather finely, with a deep, rather broad medial furrow 

 which is bounded by a high crista on each side, the lateral carina 

 sharp, foveolate externally, sides with some coarse stride; petiole 

 elongate, linear, not swollen or nodose, narrowed toward base on 

 its anterior third, in length longer than thorax, subdentate on each 

 side before middle, beneath strongly carinate down middle, at 

 apex with a broad shallow depression ; second segment above finely 

 and closely punctured, beneath shining with larger, sparse, punc- 

 tures, pedicel rather robust, long, but barely half as long as first 

 hind tarsal joint, the segment gradually dilated; radial side of 

 second submarginal cell about equal to the distance between the 

 first transverso-cubital and first recurrent nervures on the cubital 

 nervure; third submarginal cell a little narrowed above, rhom- 

 boidal, the outer nervure sinuous. Length 14 mm. 



(^. — More coarsely sculptured. Clypeus entirely yellow, more 

 than twice as broad as long, with two acute teeth anteriorly; first 

 joint of flagellum shorter than the two following united, the ultimate 

 joint obtuse at tip, longer than the penultimate, the two together 

 nearly as long as joints 10 and 11 united; lateral angles of pro- 

 notum acute and prominent; middle segment above with coarse 

 rugte. Length 12 mm. 



Chapada, September; Santarem. The ? specimen comes from 

 the former, the cT from the latter locality. 



Saussure's suggestioni that the genera Elimus and Labus might 

 be united is worthy of further thought. In fact it is diflicult to 

 understand why Elimus and Xa6tt.5_should be [considered distinct 

 from Zethus. 



' Syn opsis American Wasps, p. 56. 



