NO. 1938. THE DIPTEROUS FAMTT.Y PHORTD/E—MALLOCH. 453 



Frons distinctly longer than broad, center pair of bristles much lower on frons 

 than outer pair which are not very close to eye-margin, arista only at most aa 

 long as frons. . .• submarginalis, p. 458. 



5. Hind tibial cilia (7-8) very weak juli, p. 459. 



Hind tibial cilia (12-13) strong perdita, p. 459. 



6. Antennae brown-black, scutellar bristles of equal size, arista thin and much longer 



than frons nigriceps, p. 460. 



Antennae yellow, arista short and thick, barely as long as frons, anterior scutellar 

 bristles much reduced in size loinnemana, p. 461. 



7. Thorax' wholly and abdomen wholly or partly yellow. If there should be any 



doubt as to whether a species falls into this section it may be decided by an 

 examination of the pleurae; which in this group is always yellow, being lighter 



in color as a general rule than the dorsum.) 8. 



Thorax black or brown, abdomen black or brown, with only the hind margins of the 

 segments naiTowly paler, yellow or whitish 30. 



8. Scutellum with four bristles, the anterior pair being at least half as large as posterior 



pair in female, but sometimes much reduced in size in male 9. 



Scutellum with only two distinct bristles in female, sometimes two weak hairs 

 may be present but they are always much weaker than one-half the posterior 

 pair, and not bristle-like 17. 



9. First costal division much longer than the second, at least one and one-half times 



as long, fringe long 10. 



First costal division only about as long as second, never noticeably longer, fringe 

 generally short 13. 



10. Costa distinctly short of wing middle, first division three times as long as second, 



frons with yellow pubescence anteriorly; small si^ecies 1-2 mm . . .aletise, p. 462. 

 Costa to about wing middle, first division about twice as long as second 11. 



11. Female ovipositor exserted, chitinous; third segment of abdomen with a regular 



preapical row of hair-like bristles, and several on the lateral margins; abdomen 



conical conica, p. 462. 



Female ovipositor not chitinous, abdomen normal, without noticeable bristles 

 on third segment as in conica 12. 



12. Female proboscis large and fleshy, protruding; antennae yellow, darker at apex. 



fisheri, p. 463. 

 Female proboscis normal, retracted, antennae brown insequalis, p. 464. 



13. Mesopleurae with one strong backwardly directed bristle, small bristles very 



indistinct or absent, anterior pair of scutellar bristles unusually reduced . . 14. 



Mesopleura bare, the antei'ior pair of scutellar bristles always strong in female 



but sometimes much reduced in male 15. 



14. Two pairs of neai-ly equal post-antennal bristles, costal fringe of moderate length, 



hind and mid femora without strong bristle-like hairs on ventral surface. 



macrochieta, p. 464. 



Only one very short pair of post-antennal bristles, fringe very long, hind and 



mid femora with 2-3 very long curved bristle-like hairs on apical third of 



ventral surface spinifemorata, p. 465. 



15. Hind tibial cilia on basal two-thirds very strong and widely placed except at 



extreme base, ceasing abruptly at apical third to ])e replaced by 4-5 small 

 hair-like setulae, one very long terminal setula at apex, second abdominal 

 segment with 4-5 very long and strong bristles on lateral margins in both sexes. 



ruficornis, p. 466. 



Hind tibial setulae not abruptly reduced on apical third, generally strongest on 



that part, lateral bristles on second segment more numerous but weaker 16. 



1 Immature specimens are always paler in color, even in the black section. 



