116 Bulletin Wisconsin Natural History Society [Vol. 13, No. 2 
specimens the wings measure only 1.35 mm., while some excep- 
tionally large individuals measure as much as 2.65 mm. The 
average, however, is somewhat below 2 mm. 
Adults have been bred as follows: Lot I, January 1 1th— 16th, 
1915; February 18th-22d, 1915. Lot II, February 2d-7th, 
1915. This form would therefore seem to have a life history 
extending over about five to six weeks. 
LITERATURE 
Haseman, Leonard. 1907 A Monograph of the North American Psy- 
chodidae, IncludingTenNew Species and an Aquatic Psychodid 
from Florida. Trans. Am. Ent. Soc., 33, pp. 299-333, pls.V-VIII. 
Literature till 1907. 
Banks, Nathan. 1907 Proc. Ent. Soc. Wash., 8, p. 148. 
1914 Two New Species of Psychoda. Ent. News., 25, pp. 
127-128. 
Fullaway, David T. 1907 Immature Stages of a Psychodid Fly. 
Ent. News., 18, pp. 386-389. 
Grunberg, K. 1910 Psychodidae, in Diptera: Heft 2A, of Brauer, Die 
Suesswasserfauna Deutschland, pp. 20-25 et al. 
Haseman, Leonard. 1908 Notes on the Psychodidae. Ent. News., 
19, pp. 274-285. 
Jacobfeuerborn, H. 1914 Die Psychodiden und ihre Metamorphose. 
SB. Naturf. Ver. preuss. Rheinlande u. Westfalen 1913B, pp. 
11 - 20 . 
Welch, Paul S. 1912 Observations on the Life History of a New Spe- 
cies of Psychoda. An. Ent. Soc. Am., 5, pp. 411-418, pis. 31-32. 
Williston, Samuel W. 1908 Manual of North American Diptera. 
Psychodidae, pp. 92-93, et al. 
DIAMESA MENDOTAE sp. nov. 
A large number of larva and pupae were taken from Merrill 
Springs and Merrill Creek, both of which feed Lake Mendota. 
These specimens were obtained at various times during summer 
and fall and although a number of attempts were made to breed 
them only one was successful owing to difficulties of approx- 
imating life conditions. 
In attempting to determine the larvae and pupae without 
having bred adults (at the time) the larva seemed to belong to 
Thalassomyia, while the pupa belonged to Diamesa. The bred 
adults proved to be an undescribed species of Diamesa. 
