ARRHENURI FROM WASHINGTON AND ALASKA 
Ruth Marshall 
In the summer of 1922 the author made an extended trip to 
Alaska, from Seattle to Kodiak Island. A number of localities in 
Alaska and the Canadian Northwest were visited and water mites 
were collected in many small bodies of water. The preliminary 
work on the study of this material has been done; it is proposed 
to publish in the near future a complete account of the species 
found and their distribution. The present paper is an account of 
the Arrhenuri of the collections. 
Arrhenurus tacomaensis nov. spec. 
PI. VII, fig. 1-5 
While en route to Alaska, the author had an opportunity to 
make small collections of water mites in two localities in the state 
of Washington. The first place visited, July 7, 1922, was the inlet 
of Union Bay, at Seattle, near the University of Washington. In 
the shallow water, bordered by tall grasses and other plants, six¬ 
teen individuals were found, representing four different genera 
(Limnesia, Neumania, Fiona and Arrhenurus). There was but 
one Arrhenurus, a male; this proved to be A. krameri Koenike, 
which has already been reported by the author from Oregon. 
The second collecting ground was at Tacoma, September 4. 
Near the car-line at 52nd Street is a small shallow pond filled 
with yellow pond lilies in which seven individuals were found. 
Five of these are undetermined species of Fiona and Unionicola. 
The remaining two specimens are Arrhenurus males of a new 
species which has been given a specific name indicative of the local¬ 
ity from which it was first reported. 
A. tacomaensis belongs to the subgenus Arrhenurus and some¬ 
what resembles A. lautus described by Dr. Koenike from Alberta. 
The body is stout; two sickle-shaped projections arise dorsally at 
the place where the body passes abruptly into the appendix. This 
