1913] 
Burrill, The Giant Midge, Chironomus plumosus. 
137 
duction of fish is correlated with the plant growth,. . the lake may 
be considered simply as an expansion of Fox River. .At the south 
end the shore is swampy.” This is worthy o fnote since larvae and 
pupae were collected from swamps at Cayuga Lake, Ithaca, New 
York, the former being blood red and about 22 mm. long (Jo- 
hannsen 1905, 236-7; Westwood 1840, 516). 
In a description of that part of the lake near which the midge 
observations were made, Marsh says,'“The west shore of the lake 
is low, but not, to any considerable extent swampy, and is gradu¬ 
ally being dotted over with summer cottages.The bottom 
of the lake is generally composed of a fine mud filled with organic 
matter.” (p. 6, do.) “Lake Winnebago can not be said to have 
an abyssal fauna, the animals of the bottom in the deeper parts of 
the lake not differing appreciably from those of the littoral region.” 
Then follows a long list of species of Bntomostraca and algae with¬ 
out a word as to blood worms occurring in the larval or pupal 
stage in the plankton, though collections were made twice a day 
all summer and in winter. Dean E. A. Birge, director of the Wis¬ 
consin Geological and Natural History Survey, under whom the 
Winnebago studies were made, does not (1912) recall any Chiron- 
omids in the plankton; but Prof. Marsh (in litt. Feb. 2, 1912) 
states “Chironomus larvae are very abundant in the mud at the 
bottom of Lake Winnebago; I do not remember to have found 
them in so great numbers in any other locality. I made no attempt 
to determine the species. I do not now remember that they ever 
formed a part of the plankton.” 
Marsh makes further remarks on the interrelations of animal 
and plant life, relations which must affect the abundance of 
plumosus , as follows (1903, 40) : “The real determining cause for 
the maximum of Daplmia hyalina early in September, 1900, was 
the enormous number of Anabwna, Clathrocystis, and an unnamed 
alga.” These algae make up what is called (p. 36) the “bloom” 
or the “working of the lakes,” a phenomenon (p. 37) “especially 
ntarked in Lake Winnebago in some summers. It is due, of 
course, to the enormous growth of the plants of the plankton, that 
growth being particularly fostered by the hot weather of mid¬ 
summer. The plants especially concerned in forming the bloom 
are Clathrocystis, Anabcena, Aphanizomenon, Oscillaria, Lingbra, 
and Gloiotrichia .Following the maximum period of the 
