the A[)idce in the British Museum. 453 



3. (2) Face and pleura sometimes faintly 



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



4. (1) Testaceous species ; heail and tboriix [(tyjie of subgenus 



mostly with a coppery iridescence ; iMez/alujitidia), 



abdomen, as a rule, testaceous. 



5. (6) Scutellum bituberculate. Length 



11 mm bituherculata, Smith 



6. (5) Scutellum unarmed. [(1653) (type of genus). 



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



any longitudinal sulcus. 



8. (11) Sternite 3 entirely 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 .. ar//oj'</e«, Vach. (1904). 



11. (8) Sternite 3 black at base ochrias, Vach. (11)04) 



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 (^ff's, Vach. (1904). 



14. (13) Postscutellum shorter than scutellum. athantis, \&ch. (190i). 



M. texana (Cress. 1872), from Texas, and M. {Megaloptella) ipomoea>, 

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

 ence between the Vachalian species will be fomid 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, 

 thoracc latiori, gcnis gibbosis, utrinque infra tuberculatip ; man- 

 dibulis falcil'ormibus ; alls Bubhyaliuis. 



Long. 15 mm. 



Head for the nio.«t part and tliorax greenish bronze ; aji- 

 tenna?, clypeus at apex, mandible.s (except apically), labruni, 

 tegulse, abdomen, and legs testaceous ; the whole covered 

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

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

 much swollen, produced below to form a conspicuous tubercle ; 

 eyes slightly emarginate, inner orbits converging above but 

 ])arallel 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 anteuTiae hardly longer than joint 4. Ba.^al 

 area of median segment about half postscutellum in length, 

 of equal width transversely, the middle with a longitudinal 

 keel and stria?^ colour of chitin a deep purple. Abdomeu 



