262 ERNEST A. BACK. 



and extending upward slightly at the transverse suture, to, but not 

 including, the humeri; from thence extending upward to near the 

 center of the dorsum and thence straight back to an imaginary line 

 drawn between the posterior callosities, thus leaving the space usually 

 occupied by the median geminate stripe as a clear black undivided 

 stripe. The humeri are pruinose in certain lights, but more whitish. 

 Abdomen polished black, with bluish reflections; otherwise as above 

 Legs wholly dark chestnut; tarsi a trifle lighter. Pile of coxa? white, 

 of femora very fine, entirely white, with no black bristles; tibiae and 

 tarsi almost entirely with black pile and bristles. Wings hyaline, but 

 distinctly clouded on the distal portion of the costal cell, proximal 

 portion of marginal cell, along the anterior cross-vein and all the veins 

 closing the discal cell before, above, and behind, and at the furcation 

 of the third longitudinal vein. 



Type. — Single female, in the collection of Prof. C. W. John- 

 son, Curator of the Boston Natural History Society. 



Habitat. — Mt. Kearsarge, N. H. ; collected September 13 j 

 1903, by Dr. G. M. Allen, in honor of whom I have named this 

 species. 



Cyrtopogon bimacula. 



Euarmostus bimacula Walker, Dipt. Saund., Pt. II, 102, PL IV, 

 fig. I, 1851 



Cyrtopogon melanopleurus Loew, Cent., VII, 61, 1866 (female). 



Cyrtopogon bimacula Loew, Berl. Ent. Zeit., 1874, 365, syn. 

 cj 1 $. — Length 9-11 mm. — $• — Black; front and face densely yel- 

 lowish-brown pruinose; abdomen polished blue-black, segments 2-5 

 white pruinose on the posterior lateral margins; wings with two large 

 brown spots. 



Face and front densely yellowish-brown pruinose, occiput grayish 

 pruinose; pile of face dense, pale yellow on the middle of the gibbosity 

 and reaching nearly to the antennas; black on the outer side, on the 

 oral margin and just beneath the antennas. The latter black, first 

 two segments black-haired. Front and upper occiput with fine erect 

 black pile, which, on the ocellar tubercle, is longer and forms a distinct 

 tuft; lower occiput, base of proboscis, sides of pro thorax and all the 

 coxas with fine white pile. Thoracic dorsum yellowish-gray pruinose ex- 

 cept the humeri, along the dorso-pleural suture narrowly, more broadly 

 over the base of the wings, the posterior callosities, two spots adjoin- 

 ing the scutellum in front and the scutellum, except the extreme base, 

 which are polished black. The brown geminate stripe is distinct, 

 but not clearly defined and is abbreviated posteriorly. When viewed 

 from before two small dark brown spots are visible about the humeri 

 and two much larger ones before the transverse suture and blending 



