280 J. M. ALDRICH. 



9. All tarsi wholly black (Brazil) glltlula Wiedemaini. 



Fore tarsi wholly pale, middle ones hlack, with narrow silver fringe above 

 on last two joints (Mex., Brazil) (Iifl'ii»«ii»« Wiedemann. 



Fore and middle tarsi little infuscated, 4th joint of latter pure white, not en- 

 larged (W. I., Mex, Brazil) belliilns Aldrich. 



Fore tarsi infuscated. except part of first joint 10. 



10. Knob of halteres infuscated 11. 



Knob of halteres yellow 16. 



11. Wings with only a faint cloud, before the third vein. . .cilipes Aldrich. 

 Wings with two erossbands, or at least the hind crossvein infuscated. .. -12. 



12. Middle and hind tibise entirely black 13. 



At least middle tibiae largely yellow ; 14. 



13. Middle metatarsi ciliated above (Cuba) pilosiiM Loew. 



Middle metatarsi not ciliated above (Mex.) iuoriistlus Aldrich. 



14. Middle metatarsi ciliated (Mex., Brazil) triseriatus Aldrich. 



Middle metatarsi not ciliated • ■ 15. 



15. Third and fourth joints of hind tarsi subequal, a little swollen (Mex.). 



atricauda Aldrich. 

 These joints of normal structure (Cuba, Jamaica, Brazil). 



jucuiidus Loew. 



16. Apical third of fore coxa, with trochanter and base of femur, yellow (Mex.). 



coxali$« Aldrich. 

 Not more than extreme apex of fore coxa yellow 17. 



17. Middle tibia with a row of small bristles on the front of the inner side, ex- 



tending the whole length (Mex.) genualis Aldrich. 



Middle tibiae with a row of stout bristles on outer side, middle metatarsus 



ciliated (Mex., Brazil) triseriaius Aldrich. 



Middle tibiae with only the usual bristles 13. 



18. Last two joints of hind tarsus flattened 19. 



Last two joints of hind tarsus not flattened 20. 



19. Crossbands broad, including half the wing (Brazil). .. -gracilis Aldrich. 

 Crossbands narrow, scarcely a fourth of the wing darkened iMex.). 



flepressiis Aldrich. 



20. Middle tarsi entirely infuscated (Mex.) piirpiiratuiii Aldrich. 



Middle tarsi broadly yellow at base 21. 



21. Hypopygium minute, appendages inconspicuous (Mex., Brazil). 



siuiilis Aldrich. 

 Hypopygium large, the appendages large, flattened, black (Mex.). 



atrolainellatiis Aldrich. 



22. Face with abundant slender hairs 23. 



Face bare ' ~7. 



23. Face with dark hairs (Mex., Brazil) barbatiis Aldrich. 



Face with pale hairs ... 24. 



24. First joint of middle tarsus beset with crooked bristles 25. 



First joint normal 26. 



25. Tip of abdomen with a tuft of strikingly long hairs (U. S., W. I., Mex., 



S. A.) (mndatulus Loew) caudatus Wiedemann. 



Tip of abdomen with only ordinary hairs (U. S.). . • scobinator Loew 



26. Middle tibiae with a strikingly long apical spur (U. S.)...calcaralus Loew. 

 Middle tibia without unusually long spur (U. S.) iiierinis Loew. 



