AMERICAN DIPTERA. 389 



Nicocles pictus. 



Pygostolus pictus Loew, Cent., VII, 30, 1866. 



f Dasypogon amastris Walker, List, II, 362, 1849. 

 9 . — Length 10.6 mm. — Translation from Loew. — Black; wings beau- 

 tifully variegated with black, basal and third hyaline; third segment 

 of antennae slender, brownish, four times as long as the style. 



From a female of Pygostolus (Nicocles) dives, to which it is 

 very much aHke, the female pictus is distinguished by the 

 following marks. The antennas are a little longer, the third 

 segment is much more slender, brownish, toward the apex 

 mostly reddish, and the style much shorter. The thorax is 

 much more convex, more broadly bordered with gray on the 

 dorsum. The wing-picture is very much the same, but less 

 obscure. 



The description of Walker's amastris is as follows: 



"Black, polished, clothed with white pile, abdomen fulvo-pilose, 

 the apex obscurely reddish; antennae black; legs reddish, tarsi darker, 

 hind tibiae subarctate, hind tarsi broad, wings subcinereus, and sub- 

 fasciate with fuscous. 



"Body black, polished; head a little broader than the thorax, dull 

 and punctured above, with a row of tawny bristles on the clypeus; 

 clothed behind and beneath with white hairs, a little broader than the 

 thorax: there are a few tawny hairs on the ocellar tubercle; proboscis 

 black, its tip clothed with short tawny hairs. Antennae black, not 

 longer than the head; segments 1 and 2 short, of equal length, clothed 

 with short tawny hairs; segment 3 red, linear, darker at the tip, full 

 twice the length of the first two segments taken together; style spine- 

 shaped, dark red, slender, black at tip, about one-third the length of 

 the third segment. Eyes red, divided into two regions; the inner part 

 small, fiat, composed of large facets, which, however, successively de- 

 crease in size as they diverge to the outer part, which is convex, com- 

 posed of small facets, and much larger than the inner part, which it 

 half encircles. Chest and breast finely punctured, thinly covered with 

 white hairs; the former having also a few long tawny hairs on its pos- 

 terior part. Abdomen thin, increasing in breadth, from base to the 

 tip, full twice the length of the chest; segments 1-2 very short, the 

 third and following to the sixth, long; the seventh and eighth dull, 

 flat, large, very finely punctured, with no hairs; the seventh slightly 

 red on the hind border and on the side borders, having on each side 

 five large punctures disposed by twos and threes in two oblique rows; 

 on the eighth segment the red overspreads more of the surface and it 

 has on its side three more indistinct punctures which are arranged in 

 a more oblique row; venter dull, punctured; segments with a rim on 



TRANS. AM. ENT. SOC, XXXV. SEPTEMBER, 1909 



