36 E. T. CHESSON. 



with the description of plagifera Andre, but the head above is 

 ornamented with two oblique silvery lines, and the cheeks and 

 clypeus are also silvery; it may prove to be only a variety. 



46. M. bombyciiia 9 ■ — Length 10 mni. — Head quadrate, broader tliau 

 thorax, space behind the eyes broad, the cheeks carinate beneath, eyes rounded, 

 convex, polished ; thorax fiddle-shaped, anterior angles of prothorax acute, lat- 

 eral margin of niesothorax irregularly toothed, of nietathoras serrate; flanks 

 excavated, smooth and polished ; abdomen elongate, the first segment broadly 

 dilated at apex and conforming in outline with base of second segment. 



Black, densely clothed with appressed silky brownish ochraceous pubescence, 

 which is silvery in certain lights; when viewed from above there is an obscure 

 silvery spot on each side of the head, and a broad silvery stripe on each side of 

 thorax ; legs black, with pale glittering i)ubescence, calcaria very long and white ; 

 on each side of second abdominal segment above, about the middle, two small, 

 round, pale yellow, smooth shining spots, somewhat obscured by the sericeous 

 pubescence; apical segments thickly clothed with silvery pubescence. 



Chapada. One specimen. Differs from all the species examined 



by the uniform pale silky appearance. 



47. M. cstriiii|;ena 9- — Length 7-8.5 mm. — Head very large, quadrate^ 

 slightly narrowed posteriorly, broader than thorax, posterior margin deeply 

 emarginate, with acute lateral angles; cheeks on each side beneath with a sharp 

 longitudinal carina, extending to posterior angles above, and ending anteriorly 

 in a blunt tooth ; eyes rather small, round, convex, smooth and polished ; space 

 behind eyes about equal to width of thorax anteriorly ; thorax small in compari- 

 son with the head, fiddle-shaped, anterior angles rounded, lateral margin of 

 mesothorax with two or three small teeth, that of metathorax coarsely serrate or 

 spinose; legs slender, middle and hind tibise with five or six long slender sjjines 

 on outer margin, joints of tarsi long and slender ; basal segment of abdomen sub- 

 nodose, dilated posteriorly, the anterior face almost perpendicular, subapical 

 margin not dentate. 



Black, with sparse erect black hair, face and cheeks silvery ; a longitudinal 

 subohlique stripe behind each eye, and a broad stripe on each side of thorax 

 above, extending to apex of metathorax, silvery pubescent; mandibles dark fer- 

 ruginous; sides of thorax silvery sericeous ; legs fusco-ferruginous, clothed with 

 silvery pubescence, calcaria whitish ; a large, rounded, opaque, sanguineous or 

 bright ferruginous spot on each side of second abdominal segment; anterior face 

 of first a7id sides of the following segments with silvery pubescence; a silvery 

 spot on apical middle of all the segments above; venter fusco-ferruginous, clothed 

 with pale pubescence. 



Chapada (April to October). This may prove to be Mayri Kohl. 



48. M. Pertyi Dalla Torra (Catal. Hym., viii, p. 72; bucephahts \\ Smith, Brit. 

 Mus. Cat. Hym., iii, p. 53). — J. — Length 10 mm. — Head very large, subglobose, 

 much broader than thorax, densely punctured, posterior angles rounded ; cheeks 

 beneath with a sharp longitudinal carina; eyes small, round, convex, shining, 

 minutely netted ; thorax above closely punctured, gradually narrowed posteriorly. 



