2G Annals Entomological Society of America [Vol. VI, 



19. Abdomen yellow with black bands 22 



Abdomen yellow without black bands 20 



20. Fourth joint of front tarsi nearly two-thirds as long as third, last four joints 



infuscated 14 disjuncta . 



Fourth joint only about one-third as long as third, fifth joint black 21 



21. Wings hyaline, tinged with yellow, veins yellow 9 floridula 



Wings with a cloud at tip, tinted with brownish, veins brownish 



10 floridula var. infuscata 



22. Dorsum of the thorax with the flattened space -before the scutellum yellow.. 23 

 Dorsum with the flattened space blue or black 24 



23. Dorsum of the thorax yellow, immaculate 14 disjuncta 



Dorsum with two or three black spots 8 maculata 



24. Flattened space before the scutellum a beautiful greenish blue (West 



Indies) 7 signifer 



Flattened space black 25 



25. All the hairs and bristles of the front and middle coxae yellow. . . .3 dimidiata 

 Hairs and bristles of the middle coxae mostly black 26 



26. Front tibiae with a row of bristles 27 tibialis 



Front tibiae plain 27 



27. Front metatarsi about one and one-fourth times as long as their tibiae. 



1 rubella 

 Front metatarsi about equal to their tibiae 2 perplexa 



FEMALES. 



1 . Dorsum of the thorax largely yellow 16 



Dorsum mostly blue, green, or blackish 2 



2. Dorsum of the thorax bright shining blue. (West Indies) 3 decora 



Dorsum green or blackish 3 



3. Dorsum bright shining green 15 viridis 



Dorsum dull greenish or blackish 4 



4. Dorsum dull greenish 5 



Dorsum black or gray 14 



5. Tip of the fourth vein ending distinctly before the apex of the wing 6 



Tip of the fourth vein ending in the tip of the wing, or nearly so 7 



6. Tergum of the last two segments of the abdomen dull green, middle and 



hind femora each with a bristle near the tip 26 setosa 



Tergum with more or less brilliant green, femora without a bristle near 

 the tip 25 lateralis 



7. Abdomen f asciate 9 



Abdomen of nearly uniform color 8 



8. Large species, 4.5 mm. (New Mexico) 30 australis 



Smaller species, 2 mm. (Eastern species) 32 minuta 



9. Wings strongly tinged with yellow on the costal edge 10 



Wings nearly uniform grayish hyaline 11 



10. Wings with distinct clouds at the tips of third and fourth veins. .18 deformis 

 Wings evenly tinged along the front, not darker at tip 17 arcuata 



11. Dorsum of the thorax covered with brown pollen which nearly hides the 



ground-color. (Calf.) 24 lienosa 



Dorsum with grayish, or white pollen 12 



12. Pleurae and dorsum without yellow, except the humeri and sometimes the 



lateral edges and posterior angles 13 



Pleurae and dorsum with considerable yellow 19 tenuis 



13. Pleura and dorsum without yellow except the humeri 20 pectoralis 



Dorsum with the humeri, lateral edges to the base of the wings, and the 



posterior angles yellow 23 tarsalis 



14. Dorsum black with the humeri, lateral edges, and two stripes extending 



forward on each side of the flattened space yellow 6 tridens 



Dorsum of the thorax gray 15 



15; Dorsum of the thorax with three metallic brown vittae 31 albospinosa 



Dorsum with two nonmetallic brown vittae 22 bivittata 



