412 Wisconsin Academy of Sciences, Arts, and Letters. 
shore, vfhile C. tentans var. is more general in its distribution. It 
is of interest that the Giant Midge, C. plumosus, so common in 
the muddy depths of Lake Winnebago, should be confined 
purely to a few rocky and gravelly areas in Lake Mendota,— 
one of the peculiar contradictions so frequently met with in 
limnological studies. C. tentans seems to begin its distribu¬ 
tion in the lake where C. tentans var. leaves off. That is, it is 
confined to sandy areas and gravel while C. tentans seems to be 
restricted to mud bottoms. 
Chironomus viridis Macquard; Chironomus pallidus Coquillet. 
The former species and its congener, C. palliatus, the latter 
the rarer of the two, were first called to my attention by their 
appearance in fish food. C. viridis emerges early in the year 
and was not met with in 1914. In 1915 I did not find it till 
August when it was quite common on plants in depths of one 
or more meters. 
Chironomus modestus Say; Chironomus flavus Johannsen. 
The two species are not abundant. C. modestus is ammo- 
philous, while C. flavus frequents plants. 
Tanytarsus exiguus Johannsen. 
This is the only species of Tanytarsus found in more than one 
locality in the lake. In each case I found it at depths exceed¬ 
ing 5 meters, where the larvae would be fairly common. 
It is characteristic of the species of the genus Tanytarsus 
that they are more or less localized in their distribution. I 
have taken T. agraylioides ( = obediens Joh. ?), lauterborni, 
muticus, bausei?, dives, etc., in the lake, but always confined 
to a single locality, so that they cannot be considered in a 
quantitative study. The habits of the larvae of this genus are 
specially interesting; many of them build cases which are re¬ 
markable for their form and variety. 
Cricotopus trifasciatus Panzer; Cricotopus exilis Johannsen. 
Of the two species C. trifasciatus is especially abundant. It 
is a shore form, nearly ubiquitous in its habitats, and is much 
eaten by fishes. - It is a common species in creeks and swamps. 
