DOLICHOPODIDJE. 79 



16. The face of the male extends below the eyes, hanging down before the 



mouth, apron-like POLYMEDON Osten Sacken. 



The face of the male reaches as far down as the lower edge of the 



eye 17 



The face of the male does not reach so far as the lower edge of the 



eye 18 



17. Third antennal joint of the male rudimentary, the long arista with a 



disk at the end MACELLOCERUS Mik. 



Antennae of simple structure. . . TACHYTRECHUS Stannius. 



18. Third and fourth veins towards the tip parallel or nearly so. . 19 

 Third and fourth veins toward the tip distinctly convergent. . 20 



19. First antennal joint bare above, third joint elongate in the male. 



PELOKOPEODES Wheeler. 

 First joint hairy above. , . . GYMNOPTERNUS Loew. 



20. The last segment of the fourth vein gradually approaching the third. 



HERCOSTOMUS Loew. 



Last segment near the middle abruptly curving forward, then grad- 

 ually resuming its former course, making a segment of a circle, the 

 concavity outwards, and ending near the third vein. 



PARACLIUS Bigot. 



21. Costal vein extending to tip of third vein, the latter part of the fourth 



vein evanescent or partially so. . . ASYNDETUS Loew. 



Costal vein extending to the tip of the fourth vein, which is of the 



usual strength. ......... 22 



22. Sixth vein wanting (minute species, not shining, the first vein reaching 



only a fifth of the length of the wing). . . . ACHALCUS Loew. 

 Sixth vein present, at least for a short distance. ... 23 



23. First antennal joint hairy above. . ..' 24 



First antennal joint bare above 29 



24. Second antennal joint with a thumb-like projection fitting into the 



inner side of the third . SYNTORMOX Loew. 



Second antennal joint without such projection. .... 25 



25. Fourth vein before the tip sharply curved toward the third, nearly 



reaching it at the margin. . . METAPELASTONEURUS Aldrich. 



Fourth vein near the end parallel with the third Or only moderately 



convergent. 26 



26. Arista dorsal, third antennal joint of usual size, palpi of male large, 



face wide. . . . . . . BIOSTRACUS Loew. 



Arista dorsal, palpi small, face very narrow. . ANEPSIUS Loew. 

 Arista nearly or quite at the end of the large, pointed third joint. 27 



