§4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 90 



Aedeagus slender, not heavily sclerotized ; dilated basally and sharply 

 pointed distally; the point is slightly upturned; vesica armed with 

 numerous fine, long cornuti. Transtilla a weakly sclerotized band 

 with slightly hairy, lateral lobes. Gnathos conical, slender; covered 

 with fine spines. Socii fleshy lobes mainly indicated by hairs. 



Female genitalia. — Genital plate broad, moderately sclerotized. 

 ostium situated at about center of plate. Ductus bursae very long 

 (permitting the bursa coupulatrix to reach extreme anterior portion 

 of abdomen), slender, gradually becoming larger to form the sym- 

 metrical bursa copulatrix; inception of ductus seminalis well before 

 ostium. Signum a small, lightly sclerotized, spined, bilobed plate. 



Alar expanse, 20-26 mm. 



Type. — ^In the United States National Museum. 



Type locality.— ''CdiXiv^ Watson," Oreg. (III-IV-1872, Walsing- 

 ham). 



Food plants. — OsmorJiiza (Dr. A. F. Braun, 1921) ; 0. occidentalis 

 Torr. (Clarke, 1935). 



Note. — Osmorhiza occidentalis Torr. Although the three species 

 of Osmorhiza [occidentalis., divaricata., and hi^evipes) that are in- 

 digenous to the State of Washington were found at Godman Springs, 

 Blue Mountains, at an altitude of approximately 6,000 feet, larvae 

 infested only O. occidentalis. An extended search was made to 

 determine the host specificity of the species, and in all localities where 

 the food plants were found rosaciliella attacked only O. occidentalis. 



Distribution. — Northwestern United States and southwestern 

 Canada. 



United States records 



Montana: Glacier National Park, $ (August 7, 1920, A. F. Braun). 

 Oregon: "Camp Watson," 9 (III-IV-1872, Walsingham). 



Washington: Godman Springs, Blue Mountains, alt. 6,000 feet, 8 S S (VIII-3 

 to 8-35) ; Pullman, 2 (III-1-98, C. V. Piper). 



Canadian records 



British Columbia: Kaslo, $ (Dyar and Cockle) ; Trout Lake, $ (lS-VIII-1937, 

 H. Leech). 



Saskatchewan: Scott, 9 (20-X-1923, Kenneth M. King). 



Remarks. — I have before me a series of 12 specimens reared from 

 Osmorhiza occidentalis and 90 from Echinopanax horridum. The 

 former series is from the interior of Washington State, while the 

 latter is from the Puget Sound (coastal) region. 



For some time I have thought that these two series represented two 

 distinct but closely related species. I am now of the opinion, how- 

 ever, that they are conspecific, but that the coastal specimens represent 

 a distinct race. The interior specimens are, with one exception, con- 

 siderably darker and more suffused than those from the Puget Sound 



