DESCRIPTION OF THE SPECIES. 323 



pulverulence and pale yellowish pile, that thorax and abdomen 

 assume a uniform grayish-yellow hue. Head yellow, except the 

 middle of the occiput, which shows a large blackish-brown spot. 

 Front rather broad, attenuated anteriorly; the usual bristles very 

 pale yellowish. Antennae dark yellow, not quite reaching the 

 somewhat projecting edge of the mouth ; the anterior corner of 

 the third joint rounded. The broad oral opening rather round. 

 Proboscis and palpi short, not reaching beyond the anterior edge 

 of the oral opening ; proboscis not geniculate. The upper side 

 of the thorax is beset with brown or brownish bristles. Scu- 

 tellum yellow, with four bristles. Ovipositor reddish-yellow, 

 flat, rather broad, somewhat shorter than the last two abdominal 

 segments taken together, beset with whitish pile. Feet yellow, 

 front femora with yellowish bristles. Wings hyaline; their 

 proximal half is somewhat less limpid than the distal one, rather 

 uniformly pictured with a loose, gray reticulation, which is 

 faintest near the anterior margin; the distal half of the wing 

 is occupied by the radiated black spot, characteristic of the genus 

 Urellia, which extends from the anterior margin to the fourth 

 vein ; this spot emits two narrow oblique rays, running towards 

 the anterior margin ; the first begins at the anterior end of the 

 small crossvein and runs to the end of the colorless stigma ; the 

 second, shorter one, reaches the margin in the middle between 

 the tip of the stigma and beginning of the black spot itself; three 

 rays run towards the apex, of which the ends of the two posterior 

 ones coincide with the ends of the third and fourth veins, where 

 they are somewhat expanded; the shortest, anterior ray, some- 

 times separated from the body of the black spot by two drops 

 only, reaches the anterior margin between the ends of the second 

 and third veins; the first two of the rays running towards the 

 posterior margin cross the middle of the second posterior cell ; 

 the narrower third ray follows the posterior crossvein and is 

 sometimes connected with the second by a gray bridge, which 

 divides the hyaline indentation between them into two large 

 drops; in the first posterior cell, above and a little before the 

 posterior crossvein there is a large hyaline drop, which, upon its 

 proximal side, is bordered with black or blackish. The third 

 vein is not bristly. 



Sab. North America (coll. Winthem); Cuba (Gundlach). 



Observation 1. — I have described T. abstersa in the Dipt. Am. 



