1981] 
Nimmo — Walker Types of Hydropsvche 
261 
While not absolutely identical (the differences may be attributed 
to geographic variation, laboratory treatment, and observer vari- 
ables), these two specimens are much more similar to each other 
than either is to the females of the most nearly related species ( H . 
betteni Ross), and I judge them to be conspecific. H. separata is 
therefore synonymised with H. confusa which has clear priority. 
Smith (1979) quotes me as considering the possibility that H. 
corbeti Nimmo may be a synonym of separata. Prior to my 
examination of the type of confusa I had decided that it was. 
However, it must now be entered as a synonym of confusa. 
In view of the taxonomic history of this species Walker must be 
attributed with remarkable insight in naming it confusa. 
Hydropsyche alternans (Walker) 
Philopotamus alternans Walker, 1852: 104. 
Hydropsyche alternans: Vorhies, 1909: 707 (sp.indet.); Betten, 1934: 
185 (prob. H. bifida ). 
Philopotamus indecisus Walker, 1852: 104. 
Hydropsyche indecisa: Betten & Mosely, 1940: 20 (as synonym of 
H. alternans ). 
Hydropsyche slossonae var. recurvata Banks, 1914: 253. 
Hydropsyche recurvata : Betten, 1934: 190; Milne, 1936 73 (as 
synonym of H. slossonae ); Ross, 1944: 99. new synonymy. 
Symphitopsyche recurvata : Schuster & Etnier, 1978: 34. 
Hydropsyche codona Betten, 1934: 187; Milne, 1936: 73 (as syn- 
onym of H. slossonae ); Ross, 1938: 18 (as synonym of H. 
recurvata). 
Fig. 4 depicts the genitalia of the holotype female of H. alternans 
(Walker) (from the Albany R., far northern Ontario). Fig. 3 depicts 
the genitalia of a female (from Wandering River, northeastern 
Alberta) which has been recognised as belonging to H. recurvata 
Banks. Again, these two females are not precisely identical, for 
possible reasons similar to those given under H. confusa above. I 
judge these two specimens to be conspecific. H. recurvata is 
therefore synonymised with H. alternans which has priority. 
