280. J. M. ALDRICH. 



9. All tarsi wholly blaok (Brazil) giitlula Wiedemann. 



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



on last two joints (Mex., Brazil) <Iifl'iiSii!ii Wiedemann. 



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

 larged (W. I., Mex, Brazil) belluliiS Aid rich. 



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 crossbands, or at least the hind crossvein infuscated- . • -12. 



12. Middle and hind tibiae entirely black 13. 



At least middle tibiffi largely yellow 14. 



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



Middle metatarsi not ciliated above (Mex.) iii4»riiatus Aldrich. 



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



Middle metatarsi not ciliated 15. 



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



atricau4la Aldrich. 

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



jucuudus Loew. 



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



coxalis 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.) geiiualis Aldrich. 



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



ciliated (Mex., Brazil) triseriatus 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.). 



(lepressus Aldrich. 



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



Middle tarsi broadly yellow at base 21. 



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



siiiiilis Aldrich. 

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



atrolainellatiis Aldrich. 



22. Face with abundant slender hairs 23. 



Face bare 27. 



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.) [candatnlus Loew) caudatus Wiedemann. 



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



26. Middle tibiae with a strikingly long apical spur (U. S.)...calcarat,us Loew. 

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



