1913] 
Burrill: Lake Michigan Swarms of Chironomids 
67 
clumsy at the business, but often succeeded in catching a midge 
just before it flew, as the midge frequently waited until touched 
before it took flight. Others flew before a black ant reached 
them. Could those that did not fly until touched have been 
sleeping in the sunlight? Such consideration suggests what all 
the midges may have been doing while at rest after their arduous 
dances. 
August 11, 1912, much greater swarms of midges occurred in 
the tree-tops about Madison, after several days of cold and rain. 
On all tree trunks were many dead misshapen and swollen midges 
of many species. A few were moored by white hyphae to the 
bark as if some Empusa culicis epidemic were rampant. This 
fungus is reported on as a chief enemy of midges in my C. plumosus 
paper above noted. It remains to add that some midges had 
swollen out on intersegmental membranes, others were worst on 
the thorax, and others were completely bloated beyond recogni- 
tion as to species, the whole body being involved. By August 
14, these bloaters were much shrunken by drying. 
ECONOMICS AND CONTROL 
As regards their economic importance little more can be said 
than that they are in their immature stages, food for aquatic 
life, and as adults, food for a few birds. As a nuisance, most of 
the species do not create the many ills I have elsewhere recorded 
for C. plumosus. Yet our public buildings are often invaded by 
them, especially where such buildings do not have their large- 
sized windows properly screened. Prof. A. S. Pearse tells me 
these flies invade the Michigan Lake Shore Biological Laboratory 
some nights so that no work can be done. 
Until we solve the exact physical control of the midge swarms, 
it will be impossible to say whether screening a building will be 
the cheaper preventive from nuisance, or an electric fan or other 
means which might stimulate their swarms to gather at points 
away from our besieged human dwellings. 
REMARKS ON LITERATURE 
These notes are mostly of quantitative value owing to lack of 
opportunity for exact identification at the time, but -in August 
better observations were made on the enormous swarms of Chiro- 
