386 ERNEST A. BACK. 



grayish stripe in front, confluent behind; the rather short and weak 

 bristles above the wing, in front of, and on the suctellum, dark brown. 

 Pleurse thickly gray pubescent. Abdomen : first two segments polished 

 black; third and fourth bright yellowish-red, very narrowly black 

 along the lateral margins; fifth and sixth of the same color, but more 

 broadly black on the sides, brilliant silvery when viewed from in front, 

 less intense and finally not apparent when seen from behind. The 

 first three segments are parallel on the sides, of nearly the same width 

 as the thorax; from the beginning of the fourth to the tip of the fifth, 

 the sides are nearly straight, but divergent, so that at the tip the 

 abdomen is fully one-fourth wider; sixth segment convex behind. 

 The abdomen is bare, except the sparse, very short, recumbent 

 hairs, very much flattened, especially at the tip, the sixth segment 

 projecting eave-like much beyond the hypopygium, which is small 

 and retracted. Legs rather slender, the tibia? and tarsi spinose, but 

 not strongly so; hind femora slender, elongate, a little thickened just 

 before the tip; hind tibia? elongate, slender on the basal two- thirds, 

 much thickened, club-like at the end; hind tarsi much thickened, es- 

 pecially the first segment, which in length is little less than the three 

 following together. In color the legs are deep pitchy black, on the 

 under side of the femora, and sometimes the tibiae, also deep red; 

 bristles and pile mostly white, wings elongate, all the posterior cells 

 open; blackish, the third, fourth and fifth posterior cells chiefly, the 

 anal cell wholly, the basal cells in part, the costal cell except the tip, 

 and slender spots along the veins opposite the distal part of the first 

 vein, hyaline." 



Type. — University of Kansas. Two males. 

 Habitat. — California (type). 

 I have never seen this species. 



Nicocles {emulator. 



Pygostolus (Emulator Loew, Cent., X, 25, 1872. 



Nicocles (emulator Howard, Insect Book, 1902, PI. XIX, fig. 4. 



$. — Length about 9 mm. — Translation. — Black; the last two ab- 

 dominal segments silvery-white pruinose, the fifth segment twice as 

 broad as it is long; wings beautifully variegated with black, the 

 third basal hyaline; third segment of the antennae hardly twice the 

 length of the style. 



Very much like dives, but distinguished by a longer abdomen, less 

 dilated toward the apex, so that while the fifth segment of (Emulator is 

 double the length of its breadth, that of dives is four times as wide as 

 long. Besides the mystax is denser, longer, and more obscure (prob- 

 ably refers to color) than in dives. It differs from pictus in having the 

 third antennal segment less slender and the terminal style longer. 



Type.—M. C. Z. 



