172 
Bulletin Wisconsin Natural History Society. [Vol. 10, Nos. 3-4. 
distinguishing character, and states that, as a rule, specimens of car- 
t)onarius are smaller than those of mitis. In specimens taken on Isle 
Royale in Lake Superior 2 he found a marked difference in size between 
the two species. 
11 specimens from Solon Springs in Douglas County and the Yel¬ 
low river in Burnett Co., both of these localities in the northwestern 
corner of Wisconsin, are small, ranging from 7 to 8 mm in length: 6 
from Divide, Vilas Co., situated in the northeastern part of the state 
are about 10 mm long, and agree in size with the specimens of mitis 
mentioned below, while 18 specimens collected by Prof. Wm. S. 
Marshall at Trout and Tenderfoot Lakes in the same County run from 
7 to nearly 11 mm. The hyaline spot in the fifth posterior cell is more 
or less visible in every case. 
C. mitis Osten-Sacken. 4 Specimens from Solon Springs, Douglas 
Co., 1 from Mercer, Iron Co., and 2 from Two Rivers, Manitowoc Co., 
are from 10 to 11 mm long, and do not show a hyaline spot in the fifth 
posterior cell. 
C. celer Osten-Sacken. Taken in the northern part of the state 
at the Nemakagon river in Burnett Co., and Mercer in Vilas Co.; in 
the southern part of the state in Milwaukee Co., and Waukesha Co. 
C. excitans Walker. A species of northern distribution that has 
been taken as far south as Pennsylvania and Illinois. The 23 speci¬ 
mens in our collection are all from the northern part of the state, 
from the following localities: Solon Springs, Gordon and the St. Croix 
dam in Douglas Co.; the Yellow river in Burnett Co.; the Apostle 
Islands in Lake Superior, Ashland Co., and Divide in Vilas Co. I have 
also seen 3 from Tenderfoot Lake in Vilas Co. 
C. frigidus Osten-Sacken. Specimens on hand from Solon Springs 
and Gordon in Douglas Co., Washington Co., and Milwaukee Co. 
C. indus Osten-Sacken. The St. Croix dam in Douglas Co.; Nema¬ 
kagon river and Yellow river in Burnett Co.; Washington Co.; Milwau¬ 
kee Co. and Walworth Co. 
C. moerens Walker. 1 specimen from Milwaukee and 1 from Army 
Lake, Walworth Co. 
C. niger Macquart. In northern Wisconsin this species has been 
taken at Solon Springs and the St. Croix dam in Douglas Co., and on 
the Apostle Islands in Ashland Co.; in southern Wisconsin, at Milwau¬ 
kee, in Waukesha Co. and Dane Co. 
C. obsoletus Wiedemann. Specimens from the St. Croix dam in 
2) James S. Hine. Diptera of the 1905 Museum Expedition to Isle 
Royale, Michigan Survey 1908. Ecology of Isle Royale, pp. 
308-316. 
