the Apidae in the British Iluseum. 453 



3. (2) Face and pleura sometimes faintly 



blue. Length 9-11 mm contradicta, CMl. (1900) 



4. (1) Testaceous species ; head and thorax [(type of subgenus 



mostly with a coppery iridescence j \_Meyaloi)tidia), 



abdomen, as a rule, testaceous. 



5. (6) Scutellum bituberculate. Length 



11 mm bituherculata, Smith 



6. (5) Scutellum unarmed. [(1853) (type of genus). 



7. (12) Sternite 3, at least at base, without 



any longitudinal sulcus. 



8. (11) Sternite 3 entirel}^ testaceous. 



9. (10) First recurrent nervure interstitial 



with second transverse cubital ner- 

 vure idalia, Smith (1853). 



10. (9) First recurrent nervure received about 



the middle of second cubital cell . . argoides, Vach. (1904). 



11. (8) Sternite 3 black at base ochnas, Vach. (l'J04) 



12. (7) Sternite 3 with longitudinal sulcus to [(type of subgenus Me- 



its extreme base. [ffaloptella, Schr.). 



13. (14) Postscutellum as large or almost as 



large as scutellum (egiis, Vach. (1904). 



14. (13) Postscutellum shorter than scutellum. (sthantiSfYach. (IdOi). 



M. texana (Cress. 1872), from Texas, and M. [Megaloptella) ipomcecp, 

 Schrottky (1912), are omitted from the above. Further points of differ- 

 ence between the Vachalian species will be found in his key (Miscell. 

 Ent. p. 113, 1904). 



Megalopta genalis, sp. n. 



^ . Capite thoraceque viridi-cupreis, nitentibus, abdomine pedi- 

 busque testaceis, omnino plerumque aureo-hirtis ; capite maximo, 

 thorace latiori, genis gibbosis, utrinque infra tuberculatie ; man- 

 dibulis falciformibus ; alis subhyalinis. 



Long. 15 mm. 



Head for tlie most part and thorax greenish bronze ; an- 

 tennae, clypeus at apex, mandibles (except apicallj), labrum, 

 tegulse, abdomen, and legs testaceous ; tlie whole covered 

 with pale golden pilosity, that on the ventral scopa longer. 

 Head very massive, rather broader than the thorax, the gense 

 much swollen, produced below to form a conspicuous tubercle ; 

 eyes slightly emnrginate, inner orbits converging above but 

 parallel below; no malar space; ocelli large, forming a 

 triangle, clypeus twice as broad as long, depressed towards 

 the apex, the apical margin raised ; labrum shining, de- 

 pressed, with a median process ; mandibles falciform, bi- 

 dentate, the outer tooth projecting considerably beyond the 

 inner. Joint 3 of antennae hardly longer than joint 4. Basal 

 area of median segment about half postscutellum in length, 

 of equal width transversely, the middle with a longitudinal 

 keel and strise^ colour of chitin a deep purple. Abdomen 



