ORTALIDiE — MYRMECOMYIA. 101 



coxae. Thoracic dorsum with a thin gray bloom , the impres- 

 sions indicating the lateral beginnings of the transverse suture 

 are more densely pollinose ; the pleurae, above the middle coxae, 

 are clothed with a very dense white pollen. The shining black 

 abdomen is much narrower at its basis ; its first segment is 

 longer than each of the following ones ; about its middle it is 

 so attenuated that its smaller anterior portion is knot-shaped, 

 the larger posterior portion funnel-shaped ; the last abdominal 

 segment is somewhat shorter than each of the two preceding 

 ones. The comparatively large hypopygium is usually pitch- 

 brownish, seldom blackish ; the first segment of the black ovi- 

 positor is flat and rather broad. Feet very slender; anterior 

 coxae yellow ; the four posterior coxae yellowish-red or chestnut- 

 brownish; all are clothed with white pollen. Front feet brownish- 

 yellow, with pitch-brown femora ; the tarsi, from the tip of the 

 first joint, are blackish - brown ; the four posterior feet are 

 brownish-black; the 'knees, the extreme tip of the tibiae and the 

 root of the tarsi brownish brick-red ; in very pale-colored speci- 

 mens the light coloring of the tarsi is much more extensive. 

 Halteres black. No tegulae. Wings hyaline, with delicate black 

 veins ; the wings, towards the basis, are very much attenuated, 

 without any posterior angle and without alula ; auxiliary vein 

 short, very much approximated to the first longitudinal vein ; 

 the latter rather stout, very gradually merging into the costa, so 

 that the stigma is narrow, linear ; second longitudinal vein very 

 long and straight ; the last section of the third longitudinal vein 

 gently inflected backwards, so that it strongly diverges from the 

 second longitudinal vein and ends in the extreme apex; small 

 crossvein perpendicular, inserted but little beyond the middle of 

 the long discal cell ; the last section of the fourth longitudinal 

 vein rather straight, only very little convergent towards the 

 third : posterior crossvein straight ; the two posterior basal cells 

 comparatively small ; the posterior angle of the anal cell rather 

 acute, but not pointed ; the sixth longitudinal vein rather short, 

 but reaching distinctly to the margin. The picture of the wings 

 consists in an obscuration of the extreme root and the extreme 

 tip ; the first extends in the costal cell a little beyond the humeral 

 crossvein ; behind the first longitudinal vein, however, it reaches 

 as far as the posterior basal cells ; the obscuration of the apex 

 has its greatest breadth at the end of the first posterior cell ; it 



