AKT. 23 TWO-WINGED DOLICHOPODID FLIES VAN DUZEE 23 



necticut, June 7; Falls Clmrch, Virginia, May 16; Erie County, New 

 York, June to August; Portage, New York, July 4; Lake Pipin, 

 Ohio, September 1; Philadelphia, Pennsylvania, September 5; Polk 

 County, Wisconsin, July; Lafayette, Indiana, May to July; Law- 

 rence, Kansas, May 12; Opelousas, Louisiana, March; and Niagara 

 Falls, Ontario, October 10. 



This species has a few distinct, but small hairs on the disk of the 

 scutellum; rohusta Johnson has even more hair on the disk of the 

 scutellum and the hairs are longer: in sciitellmis^ new species, the 

 hair on the disk is still longer and more abundant. The male of 

 'bwiaculata^ new species, has more conspicuous hair on the disk of 

 the scutellum than this species has, but the female has only a few 

 small hairs as in the female of albicans. The male of nigHcoxa, new 

 species, has a few small hairs on the disk of the scutellum, about 

 as in the male of albicans. The male of sericata also has a very few 

 minute black hairs on the disk of the scutellum. 



18. ARGYRA THORACICA, new species 



Male. — Length, 5-6 mm. Face and front wide, silvery white. 

 Palpi and proboscis black, with a little white pollen. Antennae 

 black; first joint with conspicuous hairs above; third joint not quite 

 as long as the face, rounded at tip ; arista nearly apical, scarcely as 

 long as the third joint. Lower orbital cilia and the beard white, 

 about 10 of the small upper cilia on each side black. 



Dorsum of the thorax so thickly covered with silvery white pollen 

 as to conceal the ground color, except a large spot of shining green 

 before the scutellum ; scutellum more blue, dulled with white pollen, 

 with two pairs of large marginal bristles. Abdomen with the 

 second and third segments yellow, with narrow black hind margins ; 

 first segment yellowish with a black apical border, sometimes wholly 

 black, and with long black bristles on the whole hind margin and 

 a cluster of moderately long black hair on each side ; fourth segment 

 black with a yellowish basal spot on each side ; fifth and sixth seg- 

 ments wholly black ; abdomen from near the base of second segment 

 covered with silvery white pollen, which is thickest on sixth; all 

 hairs and bristles on the abdomen black, extreme edges of all seg- 

 ments white. Hypopygium (fig. 16) more or less yellowish at base, 

 black on outer surface, sometimes wholly black; outer lamellae 

 yellow, rather slender, abruptly tapering into a point from apical 

 third ; inner appendages are a pair of yellow organs of nearly equal 

 width throughout and a little obliquely cut off at tip, inside of these 

 is a blackish organ which is a little notched at tip. 



Fore coxae yellow, usually with a brown spot at base on outer 

 side ; middle and hind coxae black, their tips and inner surface yel- 



