150 



Mr. Frederick Muir has collected the species which are now 

 described. These may be tabulated as follows: 



FEMALES. 



1. With some yellow coloration, head not elongate, area of 



propodeum rather coarsely rugose only in one species 

 smooth apically 2 



Entirely without yellow coloration, head somewhat 

 elongate Hylacus niger 



2. Sides of face more or less yellow, posterior face of propo- 



deum not surrounded by strong carinae 3 



Head entirely black, propodeum with the posterior face 

 surrounded by strong carinae except where the basal area 

 rounded by strong carinae except where the basal area 

 extends over upon the declivity Hylaeus nipponicui 



3. Clypeus without yellow markings, supraclypeal area not con- 



tracted in the middle and expanded and furrowed above 4 



Clypeus with a median longitudinal mark, supraclypeal 

 area slightly contracted in the middle, a little expanded 



and strongly elevated and channeled above 



Hylaeus gnathylaeoides 



4. Edge of collar rounded, the pubescence on its posterior face 



rather feeble 5 



Edge of collar subcarinate, acute, the pubescence on 



its posterior face relatively strong and plumose 



Hylaeus Matsumurai 



5. Smaller species (5 mm.) ; lateral face marks in a line along 



the orbits ; tegutae with a yellow spot ; collar more nar- 

 rowed medially; punctures of mesonotum shallower 



Hylacus paulus 



Larger species (7 mm.) ; lateral face marks triangu- 

 lar, tegulae black ; punctures of mesonotum closer and 

 deeper Hylaeus monticola 



MALES. 



1. Third sternite simple 2 



Third sternite with a spine on either side the disc con- 

 nected by a ridge Hylaeus gtuthylacnides 



2. Scape not greatly widened 3 



Scape broader than long, about five times as wide as 

 the pedicel Hylacus nipponiciis 



3. Supraclypeal area entirely, stripe on scape, small spot on 



tubercles, etc., yellow, apical lobe of seventh sternite more 



feebly developed Hylaeus monticola 



Supraclypeal area except margins, scape and tubercles 

 dark, apical lobe of seventh sternite more strongly de- 

 veloped Hylacus sp. 



