62 E. T. CRESSON. 



Tegnlte with a median longitiifliiial carina. 



Second abdominal segment black Species 5. 



Second abdominal segment ferruginous Species 6. 



Tegulaj without longitudinal carina. 

 Second abdominal segment black. 



Abdomen with the pale pubescence silvery white. 



First segment quadrate, or only slightly longer than wide. . -Species 7-10. 



First segment elongate, much longer than wide Species 11-12. 



Abdomen with the pale pubescence mostly fulvous Species 13. 



Second abdominal segment fulvous or ferruginous Species 14-16. 



.5. M. gracili»i Smith (Brit. Mus. Catal. Hym., iii, p. 42).— "J, .—Length 8- 

 10 mm.— Black, opaque; head, prothorax, pleura beneath wings, metathorax and 

 apical margin of segments 1 and 2 of abdomen, densely silvery-white pubescent. 

 Eyes emarginate. Anterior margin of prothorax straight, transverse, with acute 

 lateral angles; mesothorax coarsely, confluently sculptured, with several smooth 

 longitudinal cariniB, the pubescence short and black; scutellum convex, with 

 erect black pubescence, becoming longer and pale at apex ; metathorax flattened, 

 the lateral angles obtuse, and when viewed from beneath carinate; tegulse large, 

 elongate ovate, opaque fuscous, the pubescence black, a well-defined longitudinal 

 carina on middle the entire length. Wings subhyaline, darker at apex ; margi- 

 nal cell lanceolate, the apex subtruncate; first subniarginal cell small as com- 

 pared with the other cells, oblique; second subniarginal large, as long as margi- 

 nal, receiving the recurrent nervure beyond the middle, the first and second 

 transverso-cubital nervures widely separated on marginal; third subniarginal 

 complete, irregularly subquadrate, narrowed beneath and extending far beyond 

 apex of marginal cell, with the outer nervure somewhat indistinct. Legs robust, 

 the pubescence and cstlcaria white. Abdomen incurved at apes, densely, strongly 

 and distinctly punctured, clothed with a scattered long white pubescence, more 

 dense at sides and on apical margin of the segments; first segment short, quad- 

 rate, depressed ; .second segment flattened on basal middle, the i)ubescence above 

 short and black, the white pubescent band at apex more or less indented on ante- 

 rior margin; third and following segments with median longitudinal carina; 

 venter with pale glittering pubescence. 



Chapada ; Santarem ; Pedra Branca. 



6. W. iRgllllit %. — Length 9 mm. — Form much as in gracilis, but more 

 robust; black, the second and third segments of abdomen orange-ferruginous or 

 ferruginous. Head with pale pubescence, golden on front and mixed with black 

 on vertex; eyes emarginate; tips of mandibles ferruginous. Prothorax, meso- 

 thorax, pleura and metathorax much as in gracilis ; scutellum coarsely reticulate, 

 flat above, quadrate, slightly narrowed behind, sides and ai)ex margined, the 

 latter broadly subemarginate, with acute lateral angles; tegulse, wings and legs as 

 in gracilis, except that the former is shining and testaceous at apex. First abdo- 

 minal segment transverse, shorter and broader than in gracilis, black, with the 

 apical margin narrowly white pubescent; second segment punctured as in gra- 

 cilis, shining, with pale pubescence, more dense at sides and tiarrowly white pu- 

 bescent at apex ; disk of segment 3-7 longitudinally carinate, the pubescence pale. 



