AMERICAN HYMENOPTERA. 165 



3. ANTHIDIINI. 

 Scopa present ; maxillary palpi 2-joiuted, joint 2 long, hairy. . . . ANTHIDIINI. 

 Scopa absent; abdomen with whitish ornaments; axillge and scutel simple; max- 

 illary palpi 1-jointed, short, bare ; mandibles 3-deutate. -STELIDINI. 



Males. 



Abdomen with white, yellow or red ornaments; ventral segments 6; mandibles 



tridentate 3. 



Abdomen without ornaments, except pubescent bands. 



Pul villi absent; mandibles at least tridentate 2. 



Pulvilli present; mandibles bideutate 1. 



1. OSMUND. 

 Metallic greenish, bluish or purplish ; abdomen at base with a slight concavity or 

 sulcate; dorsal segments 7; ventral segments 5, the last usually re- 

 tracted ; 2 large, covering 3, except on the lateral apical angles. 



OSMIINI. 

 Black TEYPETINI. 



2. MEGACHILIN^E.. 



Axillae simple ; dorsal segments 7 MEGACHILINI. 



Axillse produced into spines on each side of scutel CCELIOXYINI. 



3. ANTHIDIINI. 



Ornaments yellow or red ; legs with colored markings ANTHIDIINI. 



Ornaments whitish; legs black STELIDINI. 



GENERA. 



1. OSMUND. 



Females. 



Malar space wanting 2. 



Malar space distinct; scopa black; face with some black hairs; vein m longer 

 than section 2 of V ; large 1. 



1. Clypeus with a large subquadrate emargination, with dentiform lateral angles ; 



malar space posteriorly with a large compressed tubercle; mandibles 

 with a large triangular inner tooth ; vein a beyond V 2 . 



Ceratosmia. 

 Clypeus entire, with a produced thickened margin ; mandibles broad, triden- 

 tate, with a basal transverse carina; vein a before V 2 . 



Centrosmia. 



2. Mandibles with an enormous dilated basal tooth, distinctly 4-dentate ; clypeus 



longitudinally carinate; labrum short; stigma large; vein a not before 

 V 2 ; joints 1 and 5 of maxillary palpi minute; scopa long, dense, yel- 

 low Gnathosmia. 



Mandibles simple at base 3. 



TRANS. AM. ENT. SOC, XXIX. APRIL, 1903. 



