58 Bulletin Wisconsin Natural History Society [Vol. 11, Nos. 1-2 
of objects away from the setting sun. We disagree in the fact 
that the early morning still found the swarms on the east side 
of the house without protection from the rays of the rising sun. 
* Radi stated in 1901 (Untersuchungen liber die Lichtreactionen 
der Arthropoden. Archiv f. d. ges. Physiol. Bd. 87 p. 429 Bonn) : 
“One cannot suppose that the midges seek the direct sunbeams or 
again the shadows, rather do they hover and swarm just as much 
in direct sunlight as in shady places. Yet I find that they so 
orient themselves in most cases that the object towards which they 
are oriented, lies between the swarm and the sun, though indeed, 
not in the plane of the object but usually somewhat above or 
below” [its apex]. His word “midges” is more in the sense of 
gnat to include Culicids, and his observations do not seem to 
distinguish Chironomids sharply. 
At the time of my above observation, May 27, another swarm 
had a position a rod east of the house in the open lot towards the 
lake bluff and apparently without orientation to the dead' young 
tree, eight feet high, which stood nearby. I would not mention 
facts of such apparent unimportance but that Radi (1901, Uber 
den Phototropismus einiger Arthropoden. Biol. Centralbl. Bd. 
21, pp. 75-86; 85-6 Leipzig. Untersuchungen liber die Lichtre- 
actionen der Arthropoden, Archiv f. d. ges. Physiol. Bd. 87 pp. 
418-466; 429M32. Bonn) claims the midges orient to particular 
objects, “trees, bushes, sign-posts, or even heads of grass, grey 
stones, foot-paths or white paper,” and the nearest prominent 
object was this dead tree, although the midges were not very close 
to it. Whether this same swarm was, on the morning of the 
28th, the one found north of the house about a rod — that is, 
three rods from the dead tree, I cannot say, for it may have been 
a different swarm. However, the swarm near the tree was missing 
the morning of the 28th, so that it is supposed some of its indi- 
viduals, if they were actuated to further dancing, would move 
to these other positions. 
Dr. Wheeler (1899, February 22, Anemotropism and Other 
Tropisms in Insects, Archiv fur Entwicklungsmechanik der Or- 
ganismen, Bd. 8 pp. 373-381 Leipzig) speaks of a swarm of Hilar a 
sp. noted over a fixed spot daily for two weeks, saying (p. 375): 
“It is difficult to account for this persistence in one particular 
spot unless it be due to some odor emanating from the soil and 
