British Hymenoptera. 



205 



(2) 1. ^ antennffi very long, not hairy, extending to 



beyond the scutellum ; J with two stout pro- 

 jecting horns on the face . . . . . . rufa. 



(1) 2. J" antennae either pilose beneath, or else not 

 nearly extending to the scutellum ; 2 f^ce 

 simple. 



(12) 3. Calcaria of posterior tibite black. 

 (9) 4. Ground colour of body black. 



(8) 5. (^ posterior metatarsi more or less dilated towards 

 the apex inwardly ; apex of abdomen bidentate ; 

 2 face with black hairs, and with fulvous on 

 the two basal abdominal segments. 



(7) 6. (^ antennse pilose beneath ; $ face sparingly 

 clothed with black hairs ; posterior metatarsi 

 scarcely more than twice as long as broad . . pilicornis. 



(6) 7. ^ antennae not pilose; $ face densely clothed 

 with black ; jjosterior metatarsi much more 

 than twice as long as broad. . . . . . . xanthomelana. 



(5) 8. (J posterior metatarsi simple, apex of abdomen 

 entire ; $ with face clothed with pale hairs, 

 and basal segment only of abdomen with ful- 

 vous . . . . . . . . . . . . parietina. 



(4) 9. Body more or less metallic. 

 (11) 10. (J 6th segment very slightly notched at the apex, 

 and somewhat crenulate on each side of the 

 notch ; J scopa black . . . . , , . . ccerulescens. 



(10) 11. (^ 6th segment rather widely notched at the apex, 



its sides simple ; J scopa red . . . . . . fulviventris. 



(3) 12. Calcaria of posterior tibife pale. 



(14) 13. g' margin of 6th segment entire ; J head and 



thorax densely clothed with black hairs . . hicolor. 



(13) 14. (J margin of 6th segment denticulate at the sides ; 



$ head and thorax clothed with brown or pale 

 hairs. 



(16) 15. Segments of abdomen fringed with golden hairs aurulenta. 



(15) 16. Segments of abdomen not fringed with golden 



hairs. 

 (18) 17. $ with a sharp tooth on the basal segment be- 

 neath ; 5 scopa fulvous . , . . . . . . spinulosa. 



(17) 18. g with a broadly-elevated tubercle on the 2nd 



segment beneath ; } scopa greyish . . . . leucomelana. 



1. Osmia rufa, Linn. (PL VIIL, fig. 9). 



Linn., Syst. Nat., ed. x., i., p. 575 ; Smith, Cat. Brit. 

 Hym., 2nd ed., p. 152. 



Head and thorax clothed with grejish brown haks, face of the J 

 with black. Abdomen entirely clothed with orange-red hairs ; face 

 of the 5 with two thick, usually bifid, horns below the antennae on 

 each side of the clypeus. 



3' . Head and thorax greenish black, closely and finely punc- 

 tured ; face clothed with whitish hairs below the antennae, with 



