292 Professor Williston on the 



both thickened ; the following joints slender, distinctly separated, 

 finely pubescent. Rostrum rounded, a little prolonged, but 

 shorter than the head ; polpi inserted towards its base, rather 

 slender, the ultimate joint shorter than the penultimate, the two 

 together about equal to the antepenultimate joint. Front rather 

 narrow ; vertex but little developed. Legs very long and slender, 

 finely pubescent ; tibiaj without spurs ; ungues simple ; no 

 empodia. Male forceps not large, in the dry specimen showing 

 two obtuse, fleshy lobes. Valves o£ the ovipositor small, slender, 

 arcuated. Auxiliary vein nearly as long as the first longitudinal 

 vein, joining the costa in an acute angle ; the subcostal cross-vein 

 at some distance before the tip. The second longitudinal vein 

 arises at some distance before the middle of the wing, with a 

 strong curve backward ; nearly opposite the distal end of the 

 discal cell, it gives off an oblique branch to the costa ; marginal 

 cross-vein long and oblique, sometimes joining the proximal end 

 of the anterior branch. The beginning of the third vein in the 

 same straight line with the first section of the second vein, 

 terminating in the fourth vein at the proximal end of the discal 

 cell. Anterior cross-vein wanting. Anal cell narrowed in the 

 margin. Seventh vein very short. 



This singular ^enus is remarkable, if my interpreta- 

 tion of the neuration is correct, in the entire absence of 

 the first posterior cell, the second submarginal cell 

 lying in contact with the discal cell and the second 

 posterior cell, through the absence of the small cross- 

 vein and the greater part of the third vein. It is difficult 

 to see how there can be any other interpretation, as the 

 branch of the second vein that takes the place of the 

 small cros?-vein cannot possibly be that cross-vein, for, 

 in that case, it would arise from the second vein — an 

 impossibility. Furthermore, this interpretation seems 

 probable from a study of the neuration in ParatwjJesa, 

 where the first posterior cell begins at the outer end of 

 the discal cell. The relationship seems to be with that 

 genus, but I cannot agree with Osten Sacken in con- 

 sidering the anterior branch of the second vein an 

 adventitious cross-vein. There are two submarginal cells 

 present, as in Gonomyia. Aside from the fact that there 

 are only three posterior cells present, which may or may 

 not be a generic character, the shortness of the seventh 

 longitudinal vein is sufficient for the separation of the 

 genus. 



