592 I'KOCEEDINGS OF THE ACADEMY OF [Oct., 



Rostrum antl palpi brown. AnteniiiE with the basal segment 

 very elongate, dark brown, flagellum dark brown. Head gray. 



Thoracic dorsum light gray, the praescutum with darker markings, 

 a very indistinct stripe on either side of the middle line, a more 

 distinct stripe on either side, narrowest in front. Pleura? light gray. 

 Halteres pale yellow. Legs, coxse and trochanters yellow, femora 

 yellow darkened at the tip, tibiae brownish yellow, brown at the tip, 

 tarsi brown. Wings subhyaline or faintly yellowish, stigma indis- 

 stint, veins brown; venation (PI. XXVII, fig. 29): Ritt about as long 

 as the basal deflection of Cu,; cross-vein r at about two-thirds the 

 length of Hi. 



Abdominal tergites gray, the hypopygium reddish yellow; ster- 

 nites blackish gray, each segment with more or less yellow at the 

 base. 



HolotjT)e, cf , London Hill Mine, Bear Lake, Brit. Col., alt. 7,00t> 

 feet, July 29, 1903 (A. N. Caudell). 



Allotype, 9 , topotypic. 



Paratypes, 10 cf 9 , topotypic. 



In the L'. S. National Museum Collection this material was deter- 

 mined as L. cubitdlis Osten Sacken, and by Osten Sacken's key* it 

 would run down to that species. The following differences suffice to 

 separate the forms: 



1. The extreme base of R2 is perpendicular to the end of the sector; 

 ceil Ri very long and narrow; wings more tinged with yellow; 

 hypojjygium concolorous with the rest of the abdomen: size 



larger (Eastern United States) aibitalis Osten Sacken. 



R2 leaves the end of the sector at an angle; cell R2 shorter, not so 

 elongated; wings nearly hyaline; hypopygimn reddish, con- 

 spicuously brighter than the rest of the abdomen; size smaller 

 (British Columbia) horlensia, sp. n. 



Limnophila nigripleura A. and L. sp. n. 



Belongs to the luieipennis 0.sten Sacken grou]); wings clear; 

 pleurtc with a conspicuous dark brown strijie from the cervical 

 sclerites to the postnotum. 



Male, length, 4.8-5 mm.; wing, 5.8 15 mm. 



Female, length, G mm.; wing 7 mm. 



Palpi and antenna; dark brownish black. Head light clear gray, 

 provided with numerous hairs. 



Pronotum dusted with gray. Mesonotal prsescutum and scutum 



*Mon. Dipt. X. -Vin., vol.4, p]). 202, 203. 



