NO. 1938. THE DIPTEROUS FAMILY PHORID^E—MALLOCS. 455 



29. Hind tibial setulse strong and distinct; wings long, the first costal division but 



little longer than second and third together longipennis, p. 473. 



Hind tibial setulae small and indistinct; wings normal, costa rather shorter than 

 in longipennis, and longer fringed, first division distinctly longer than second 

 and third together (about as in fungorum) cayuga, p. 474. 



30. Scutellum with four subequal bristles 31. 



Scutellum with only two distinct bristles, sometimes two weak hairs present 



anterior to the ordinary bristles 34. 



31. Halteres black-brown 32. 



Halteres yellow 33. 



32. Scutellar bristles on margin of scutellum johannseni, p. 474. 



Scutellar bristles not on margin, the posterior pair nearly on center of disk. 



brunnipes, p. 475. 



33. Scutellar bristles rather weaker, the anterior pair slightly smaller than the posterior 



pair; a distinct bristle on base of third longitudinal vein. 



iroquoiana, p. 476. 

 Scutellar bristles strong, the anterior pair at least as strong as the posterior. 



ursina, p. 476. 



34. Female proboscis exerted, very prominent, sometimes chitinised 35. 



Female proboscis not exserted and chitinous, generally retracted and always 



fleshy 37. 



35. Mid and hind tibiae with a single minute apical spur each 36. 



Mid tibial apical spur very long, hind tibial spur minute prohoscidea, p. 477. 



36. Female proboscis very large and swollen, fleshy, bifiu-cate; costa to distinctly 



beyond wing middle rostrata, p. 477. 



Female proboscis stout and chitinous, costa to short of wing middle, .cata, p. 477. 



37. Mesopleui-a bristly 38. 



Mesopleura bare 51. 



38. Halteres black 45. 



Halteres yellow 39. 



39. Mesopleura with one very strong backwardly directed bristles besides the numer- 



ous short bristles; costa to about middle of wing, fringe very short; fourth 



abdominal segment in female very short dliata, p. 481. 



Mesopleural bristles of equal sizes, no one bristle noticeably longer than the 

 others 40. 



40. Frons glossy black, as long as broad, costa to short of middle of wing, fringe short, 



small species, 1 mm retardata, p. 482. 



Fi'ons dusted, generally broader than long; fringe of moderate length, larger 

 species generally 1^ mm. or over 41. 



41. Extreme margin of wing tip dark-bordered, costa short of wing middle, first 



division shorter than other two together approximata, p. 483. 



Extreme margin of wing tip not dark-bordered, only sometimes the front margin 

 of wing beyond costa a little thickened and darker, but never round apex of 

 wing 42. 



42. Shining black species with bro\vn legs, only the anterior pair paler, first costal 



division equal to other two together vulgata, p. 483. 



Brown-black species, legs yellow, sometimes the posterior pair darker 43. 



43. Small species, li-2 mm difficilis, p. 484. 



Larger species, over 3 mm 44. 



44. First costal division about as long as other two together, fringe very long. 



anomala, p. 484. 



First costal division distinctly longer than other two together, fringe of moderate 



length subobscurata, p. 485. 



