BEES IN BRITISH MUSEUM. 355 



Agapostemon placidus (Halictus placidus, Sm.) <?• 



Abdomen red, head and thorax dark blue shaded with purple ; 

 eyes moderately emarginate ; first r. n. joins second s. m. near its 

 end. 



Agapostemon emargi uat us (Halictus emarginatus, Spinola) % . 



Legs yellow ; apex of abdomen strongly emarginate. See also 

 Vachal, Misc. Entom., 1903, p. 121. 



The remaining species are left for the present in Halictus, al- 

 though they are for the most part not strictly of that genus. 



Halictus rubellus Haliday 9. 



Head and thorax black ; abdomen largely dark red ; eyes deeply 

 emarginate; metathorax truncate, base shining, neither rugose nor 

 plicate; hind spur simple; b. n. strongly bent, falling some distance 

 short of t. m. ; third s. m. very large ; first r. n. joining second s. m. 

 at its extreme end. 



Halictus posticus Spinola 9. 



Eyes emarginate ; base of metathorax neither plicate nor rugose ; 

 abdomen black with the apex red ; stigma extremely large ; third 

 s. m. large, but not nearly so long as first; b. n. strongly but not 

 abruptly bent, falling a little short oft. m. ; hind spur simple. 



Halictus gayatinus Spinola 9. 



A small black species, with very large stigma, and third submar- 

 ginal cell greatly narrowed above. 



Halictus cliilensis Spinola 9. 



A magnificent species; first three segments of abdomen jet black, 

 with their hind margins broadly shining light yellow, reminding one 

 of some species of Nomia. Fourth segment tinged with purple and 

 green. Head and thorax very dark blue ; marginal cell and beyond 

 with a dark fuscous cloud ; eyes deeply emarginate ; tibise and tarsi 

 red ; base of metathorax neither plicate nor distinctly rugose. 



Halictus pro.vimus Spinola 9 • 



Head and thorax green ; mesothorax splendid peacock green ; 

 scutellum clouded with rosy-purple ; abdomen very dark purple, 

 with white hair-patches at sides of bases of segments two to four; 

 hind spur with three large teeth. 



TEANS. AM. ENT. SOC. XXXI. SEPTEMBER, 1905. 



