Vol. XI) ALEXANDER— NEW DJPTERA 107 



sternites yellow, the eighth segment black with the conspicuous 

 median lobe light yellow; ninth sternite brownish black. Male 

 hypopygium with the posterior margin of the ninth tergite pro- 

 duced into a flattened ledge with a very broad and shallow 

 V-shaped notch, the margins rugulose, sparsely setiferous, the 

 lateral angles short and subacute. Ninth pleurite small but 

 complete; outer pleural appendage very long and narrow, broad- 

 est just beyond the base, tapering gradually to the blunt apex. 

 Ninth sternite very broadly membranous beneath ; dorso-caudal 

 angle produced proximad and slightly dorsad into cylindrical 

 reddish lobes that are clothed with reddish setse. Eighth sternite 

 with a conspicuous shovel-shaped median lobe that is broadest 

 at the base, narrowed to the apex, the narrow caudal end weakly 

 emarginate. 



Superficially, Tipula optiva bears a considerable resemblance 

 to T. taughannock Alexander (Eastern North America). The 

 structure of the hypopygium, however, indicates that it is, in all 

 probability, a member of the arctica group, allied to T. subarctica 

 Alexander, T. pribilofensis Alexander, and other species. 



Holotype, male, No. 745, Mus. Calif. Acad. Sci.; E. P. Van 

 Duzee collector, July 9, 1920. 



Type locality, Northbend, King County, Washington. 



