198 robert h. wolcott: 



mentioned — A. ypsilophorus (Bonz), A. fossulatus Koenike 

 and A. {N.yingens (Koenike). 



The collection of material upon which the present paper is 

 based was begun in 1893 and has been carried on, as oppor- 

 tunity offered, ever since. During the five years the following 

 collections of Unionidae have been made and examined for 

 mites: 



August, 1893, at Lake Saint Clair, Mich., 257 specimens of 

 Unio gracilis Barnes, TJ. luteolus Lam., TJ. nasutus Say, TJ. 

 alatus Say, TJ. ventricosus Barnes, TJ. gibbosus Barnes, TJ. 

 rectus Lam., TJ. coccineiis Hild., TJ. undulatus Barnes, TJ. 

 occidens Lea, Margaritana rugosa Barnes, M. deltoides Lea 

 and Anodonta ovata Lea. 



October, 1893, at Lansing, Mich., from the Cedar River, 

 about a score of mussels, belonging to several species, the 

 record of which is, unfortunately, lost. 



July and August, 1894, at Charlevoix, Mich., from "26" 

 Lake, Twin Lakes and Susan Lake, small inland lakes in the 

 vicinity, and from Round Lake, opening into Lake Michigan, 

 and also from Intermediate Lake at Ellsworth, Mich., 116 

 specimens of TJ. luteolus, M. rugosa, A. subcylindracea Lea, A. 

 footiana Lea, A. edentula Say and A. fragilis Lam. 



August, 1894, in two small lakes on Beaver Island, L. 

 Michigan, 85 specimens of TJ. luteolus, A. footiana, A. fra- 

 gilis and A. marryatanaA,e&. 



July and August, 1895, from Grand River and smaller 

 streams, and from Reed's Lake, near Grand Rapids, Mich., 

 273 specimens of U. coccineus, U. gibbosus, U. ventricosus, 

 U. occidens, U. recfais, U. undidaPiis, TJ. plicatus Lea, TJ. 

 alatus, U. ligamentinus Lam, U. spatulatus Lea, TJ. Novi- 

 eboraci Lea, U. rubiglnosus Lea, U. pustulosus Lea, TJ. School- 

 ci'dfta Lea, TJ. verrucosus Barnes, TJ. luteolus, M. rugosa, M. 

 marginata Say, A. ovata, A. edentula, A. footiaona, A. sub- 

 cylindracea, A. fragilis, A. imbecilis Say. 



July, 1897, from Rogue River, Kent County, Mich., and 

 from Reed's Lake, Grand Rapids, Mich., 21 specimens of TJ. 



