598 PROCEEDINGS OF THE ACADEMY OF [Oct., 



elongate rostrum, from which character Coquillett evidently derived 

 the generic name. 



Genus TRICYPHONA Zetterstedt. 

 1838. Tricyphona Zetterstedt: Ins. Lapponica, Dipt., p. 851. 

 Tricyphona katahdin sp. n. 



Color light brown; wings light yellow with sparse brown seams 

 and spots ; cross-vein m-cu lacking. 



Male, length, 6-7.6 mm.; wing, 6-6.9 mm. 



Female, length, 8.8-9.5 mm.; wing, 7.5-9 mm. 



Palpi dark brownish black, rostrum and head brownish graj^, 

 clearer gray on the vertex adjoining the eyes; first segment of the 

 antennae pale yellow, remainder of the antennae dark brown. 



Mesonotal prgescutum light fawn-brown with an indistinct brownish 

 strips on either side of the middle line and shorter lateral pale brown 

 stripes, these latter continued caudad onto the lobes of the scutum; 

 scutellum grayish; postnotum light yellowish brown with a whitish 

 bloom. Pleurae light yellow. Halteres pale, the knob a little 

 darker. Legs yellow, coxae and trochanters brownish yellow, femora 

 yellow darkening into brown on the apical half or more, tibiae and 

 tarsi dark brown. Wings light yellow, the veins yellow; small 

 brown markings as follows : a rounded spot on Sc^ continued up into 

 the costal cell; an oval spot at Sci; brown seams at the base of Rs, 

 base of -R2+3, cross-vein r, tip of R^+s, fork of -R4+6, cross-vein r-m; 

 venation (PL XXV, fig. 7) : cell R4 much shorter than cell R3, usually 

 one-half as long; cell Mi very short usually about equal to its petiole 

 beyond cross-vein m or a little longer; cell 1st M2 very long, narrow; 

 Cui and Mz fused for a distance obliterating cross-vein m-cu. 



Abdominal tergites with the basal two-thirds brown, apical third 

 yellowish; sternites dull brownish yellow, margined laterally with 

 brown, the apical segments with the margin reduced or lacking; 

 hypopygium pale. 



The female is similar to the male, but larger, especially the abdomen; 

 brown tips to the femora narrower; abdomen usually with more 

 yellow color, often with a broad median patch of yellowish on the 

 tergites. 



In some of the males the scapal segments of the antennae are dark 

 brown, concolorous with the rest of the antennae. 



There is some variation in venation in the series, the fusion of 

 Mz and Cui is sometimes lacking, the cross-vein m-cu being present 

 as in vernalis Osten Sacken; one female lacks cross-vein m in both 

 wings. 



