24 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 52. 



5. Scutum with discal marks; abdominal fasciae all continuous melanosterna. 



5. Scutum without discal marks; no continuous fasciae on venter of abdomen 6. 



6. Wings distinctly infumated; lateral ventral spots on abdomen not confined to 



sternites 2 and 3 serrata. 



6. Wings hyaline; lateral ventral spots on abdomen lacking or confined to sternites 



2 and 3 plana. 



7. Apical segment of fore tarsus broadly dilated and black; process on second sternite 



blunt and strongly hirsute distally tuberculata. 



7. Apical segment of fore tarsus normal and yellow ; process on second sternite pointed 



and smooth distally callista. 



8. Medial femora smooth ; head narrower than thorax 9. 



8. Medial femora dentate or serrate below ; head normal 10. 



9. Width of the second cubital cell on the radial vein and on the cubital about equal; 



second sternite almost wholly yellow - bituberculata. 



9. Width of the second cubital cell on the radial vein about half its width on the 



cubital; second sternite mostly black emarginata. 



10. Pulvilli indistinct; apical segment of tarsi normal pulchella. 



10. Pulvilli distinct; apical segment of tarsi black; anterior pair dilated 11. 



11. Large and stout, 18-20 mm; fasciae on tergites broad and except first continuous; 



second inclosing pair of black medial spots; fasciae on sternites 1-5 continuous 

 or narrowly interrupted speciosa. 



11. Slender, about 15 mm; fasciae on tergites interrupted on 1 or on 1-3, leaving on 



one or more of these tergites a pair of yellow medial spots; yellow on sternites 

 in the form of lateral spots melampous. 



12. Head, thorax, base of abdomen and basal joints of legs covered with long, white, 



dense pubescence; most specimens but not all have the second sternite bitu- 

 berculate villosa. 



12. Pubescence of head, thorax, etc. of normal character 13. 



13. Second sternite nontuberculate tenuicornis. 



13. Second sternite unituberculate megacera. 



13. Second sternite bituberculate 14. 



14. Medial femora of normal form, not emarginate 15. 



14. Medial femora more or less strongly emarginate posteriorly 16. 



15. Scutum with a pair of large discal marks exigua. 



15. Scutum without discal marks pulla. 



16. Scape black above; mesosternum marked with black; genital stipes as in fig. 



77 .femorata. 



16. Scape entirely yellow; mesosternum yellow; genital stipes as in fig. 79. .divergens. 



Females. 



1. Pulvilli distinct 2. 



1. Pulvilli indistinct 13. 



2. Scutum without discal markings 3. 



2. Scutum with discal marks more or less well developed 5. 



3. Head narrower than thorax; width of second cubital cell on the radial vein about 



half its width on the cubital vein emarginata. 



3. Head normal, wide as thorax; second cubital cell normal 4. 



4. Spots on scutellum rectangular; spots on either side anterior ocellus pulla. 



4. Spots on scutellum triangular; V-shaped spot inclosing anterior ocellus. megacera. 



5. Discal marks consisting of a pair of irregular spots, or of lines not broken, not 



curved inward or approximated posteriorly 6. 



5. Discal marks in form of a U, either unbroken, interrupted medially, or broken 



into lines and spots 7. 



6. Scutellum with pair of large rectangular lateral spots pulla. 



