CLASSIFICATION OF THE BEES. 71 



Scutellum posteriorly truncate, the apical margin acute and projecting 

 over the metanotum ; basal abdominal segment broadly, deeply con- 

 cave, at base, the concavity superiorly acutely margined ; labial palpi 

 5-jointed, the three basal joints elongate, the last two minute; eyes 

 extending to base of mandibles, in male more or less strongly conver- 

 gent above 3. 



Scutellum rounded off posteriorly, not projecting over the metanotum ; 

 basal abdominal segments only slightly concave at base, the impres- 

 sion superiorly rounded, not acutely margined ; labial palpi 4-jointed ; 

 eyes not quite extending to base of mandibles, in % not strongly con- 

 vergent above ; intermediate legs normal. 



Xylocopa Latr. = Shornherria Lep. (Type X. violacea Latr.). 



3. Labium in 9 trilobed ; scape of antennae cylindrical, not flattened. 



Second cubital cell, along the cubitus, much longer than the first; mandibles 

 tridentate ; % with the eyes not strongly convergent above, the inter- 

 mediate legs deformed, their tarsi compressed, with a .long, lateral 

 fringe of hairs Mesotrichia Westw. (Type M. torrida W.). 



Second cubital cell, along the cubitus, shorter than the first; mandibles bi- 

 dentate; % with the eyes not or only slightly convergent, the inter- 

 mediate legs normal, but both the intermediate and the anterior tarsi 



fringed with very long hairs Koptorlliosoma Gribodo. 



Labrum in 9 unilobed, or with a median carina on ridge; scape of antenna; 



flattened ; second cubital cell, along the cubitus, about equal to tbe 



first: % with the eyes strongly convergent above, almost holoptic; 



front coxre armed with long spines beneath ; front tarsi broadly dilated. 



Platynopoda Westw. =Andmeta Lepel. (Type A', latipes Fabr.). 



4. Maxillary palpi 4-jointed, gradually tapering from the base to apex, the basal 



joint stout, about half the length of the second, the third shorter than 

 the basal joint, the apical joint slender, minute ; labial palpi 4-jointed. 

 shorter than the labium testis Lepel. 



5. Maxillary palpi wanting; first joint of flagellum, in both sexes, elongate, 



nearly as long as the scape ; eyes in 1 strongly convergent and almost 

 meeting above Oxa*a King. 



Family IX. MEGACHILID.E. 



(The Mason, Leaf-cutting and Potter Bees). 

 The bees placed in this family are exceedingly common, and are 

 found widely distributed into all regions of the globe. In the num- 

 ber of genera and species it will probably exceed all of the other 

 bee families, except possibly the Anthophoridse. 



It seems to be dividable into three natural groups, which I have 

 designated as subfamilies. These may he distinguished by the fol- 

 lowing simple characters: 



Table of Subfamilies 



Abdomen in 9 always with a ventral scopa. 



Abdomen above convex; terminal tarsal joint always with a distinct pul- 

 villus between the claws. . . Subfamily I. Osmiixje. 



TRANS. AM. ENT. SOC. XXVI. JUNE, 1899. 



