326 Professor Aldrich on the 



sometimes more brownish than black, with close black hair. Fore 

 tarsi longer than the tibiaj ; the middle and hind femora have near 

 the tip below a few bristles ; the latter not ciliated. Wings 

 almost hyaline, rather small in size, of the usual shape. 



$ . Face blackish, of ordinary structure ; third joint of 

 antennte not so large nor so deeply notched as in some of the 

 males ; halteres j^ellow. 



Length l-7-2"l mm. : of wing, the same. 



Numerous males and females. 500-2000 feet altitude. 



2. Chrysotus iwoximus, n. sp. 



Differs from the preceding species only in having the legs from 

 the knees down light yellow ; some of the males have the third 

 joint even larger ; the average size is smaller. In some specimens 

 the trochanters also are yellow. Length l'6-2 mm.; of wing, 

 the same. 



Numerous specimens, as above. 



3. Chrysotus jiavus, n. sp. 



Wholly pure yellow species ; eyes of male contiguous on the 

 face. 



(J . Palpi large, about half as long as the face, yellow ; eye 

 contiguous, leaving a blackish triangle below the antenure ; front 

 very broad at vertex, narrow towards the antennse, dark in colour,, 

 probably metallic in living specimens ; antenna; rather large, the 

 third joint a little elongated with a subapical brownish arista ; the 

 colour of the anteunfe is wholly yellow ; cilia of lateral and 

 inferior orbit yellow. Thorax with pleurae wholly yellow, the 

 bristles blackish, but in a strong light more yellowish. Cilia of 

 tegulae brown ; below the tegula a small blackish spot. Metanotum 

 strongly developed. Abdomen yellow, the dorsum blackish except 

 at base ; the first segment has a row of long hairs, black above, at 

 the sides yellow. The hair of the dorsum is blackish, of 

 the rest yellow. The abdomen as a whole is short, the hypo- 

 pygium concealed, a few minute yellow organs visible. Legs from 

 coxa to tarsus wholly pure yellow, with yellow hairs and bristles ; 

 middle and hind tibiae rather bristly, the hind tarsi with small 

 bristles below. Wings almost hyaline ; fourth vein perfectly 

 straight in its last segment, ending behind the apex. 



§ . Face very narrow, white pollinose ; palpi long, broader 

 than in the male, resting on the very large yellow proboscis. 



