250 CHARLES W. JOHNSON. 



terest in their study. The following table contains only those species 

 found north of INIexico : 



1. — Tliird longitudinal veiii branched 2. 



Third longitudinal vein simple 13. 



2. — First antennal joint less than twice the length of the second 3. 



First antennal joint more than twice the length of the second 22. 



3. — Eyes glabrous 4. 



Eyes pubescent 24. 



4. — Abdominal markings of the % 9 dissimilar 5. 



Abdominal markings of the % 9 similar 6. 



5. —Thorax : disc usually with two irregular markings biiiotata Loew. 



Thorax : disc without markings (spines of the scutellum blunt). 



varipes Loew. 



6. — Face of both sexes yellow 7. 



Face of male black, female yellow riifii>ej<» Loew 



7. — Abdominal markings triangular, attenuated and reaching the lateral mar 



gins ciiiela Oliv. 



Abdominal markings triangular, not reaching the lateral margins. 



<lor<$»lis Fabr. 



8. — Abdomen of the 9 with transverse bands; %, with dorsal line 9. 



Abdomen of the 9 with transverse tiands; % with only lateral markings 



at the posterior angles iiisequalis Loew. 



9.— Scutellum and spines yellow aiM'tiata Loew. 



Scutellum and spines black (lava Say. 



10. — Scutellum more or less yellowish, without spines 11. 



Scutellum black, with spines 12. 



11. — Scutellum wholly yellow ; black of the vertex does not extend over the 



vertical angle fallax n. sp. 



Scutellum, base black; black of the vertex extends over the vertical angle; 



proboscis longer iiigrirostris Loew. 



12. — Wings: veins very dark brown, face produced ui^erriina Loew. 



Wings : veins reddish, face rounded, front broad pilONUS Day. 



13. — Scutellum 9 wholly green ; % brownish 14. 



Scutellum 9 black, with lateral margin green ; % black. le.xasiana n. sp. 

 14. — Thorax ( 9 ) dis<' with two green stripes; % pleurae yellowish. 



triviftata Say. 



Thorax ( 9 ) disc without stripes ; % pleune black vertebrata Say- 



15. — Front and vertex black 16. 



Front and vertex red liy<lroleonoi»les n. sp. 



16. —Pile (pubescence) on the mesouotum short 17. 



Pile (pubescence) on the mesouotum moderately long, .aiiieric-ansi Day 

 17. — Abdomen with a wide dorsal line, usually narrower in the % than iu the 



female 18. 



Abdomen: doi'sal line wanting; second, third, fourth and fifth segments 



entirely green Al«lrielii n. sp. 



18.— Front without yellow spots virgO Wied. 



Front with yellow spots |>iliiii»iia Loew. 



