AMERICAN DIPTERA. 



281 



27. Arista at least two-thirds the length of the entire body 28. 



Arista much shorter ^0- 



28. Arista ending in a small disk, fore metatarsus not with long cilia above 



(Mex.) nobilissiimis Aldrich. 



Arista plain, fore nietatarsus with long cilia above 29. 



29. Appendages of hypopygium pale, middle metatarsus also ciliated (U. S.). 



coinatns Loew. 

 Appendages of hypopygium blackish, middle metatarsus plain (U. S.). 



crinitus n. sp. 



30. Thoracic dorsum covered with thin white dust, front densely silvery-polli- 



nose(Mex.) argeiilatus Aldrich. 



Thorax and front iliostly shining 31. 



31. Costa with a row of erect cilia 32. 



Costa without erect cilia 33. 



32. Second joint of fore tarsus shorter than any of the following (U. S.). 



((■Hiatus Loew) iniiii<lii»i Wiedemann. 

 Second joint longer than any following (Mex.) liirtipes Aldnch. 



33. Middle metatarsi with erect cilia above (Mex.) ciliipes Aldrich. 



Middle metatarsi not so ciliated 34. 



34. Middle tibite yellow, color of body purple (Mex.) |>iir|»nreus Aldrich. 



Middle tibiffi yellow, color of body green (Mex.) forcipatiis Aldrich. 



Middle tibise black (U.S., W. I.) chrysoprasius Walker. 



35. Wings with dark markings 36. 



Wings wholly hyaline '^^^ 



36. AntennjB yellow (Brazil, Mex.) basilaris Wiedemann. 



Antennae black 37. 



37. The hyaline space between the crossbands extends forward to the second 



vein 38. 



Hyaline space not reaching beyond third vein 40. 



38. First joint of fore tarsus white at tip, the following joints black, the fourth 



fringed above with black (Mex.) iiiterceptns Aldrich. 



Fore tarsi plain, gradually infuscated 39. 



39. Fore coxa black (Mex.) peiiiiifer Aldrich. 



Fore coxie yelUow (Mex.) flavicoxa Aldrich. 



40. Cilia of tegulaj pale on lower half, third vein curved forward at tip (Brazil). 



imperator n. sp. 



Cilia of tegulse black "^l- 



41. Second and thirds joints of fore tarsus stout, swollen, bristly (Mex.). 



clavipes Aldrich. 



Fore tarsi plain, or only bristly 42. 



42. Fore cox* green (U. S.) viridicoxa n. sp. 



Fore coxse pale ^3. 



43. Middle metatarsus with a row of erect cilia on fore side (U. S.). 



scaber Loew. 



Middle metatarsus plain (U. S.) • siplio Say. 



44. Face with numerous pale hairs (U. S.) flavipes* u. sp. 



Face bare '*^* 



45. Middle metatarsi greatly elongated, ciliated (W. I.). • • -insularis Aldrich. 

 Middle metatarsi plain, short (Mex.) tonsus Aldrich 



TRANS. AM. ENT. 80C. XXX. (36) OCTOBER. 1904. 



