. The Clear Lake gnat. Diptera; Diptera. University of California—Experiment Station midafternoon, especially on hot days, the gnats may be found resting on the trees, tules, grass, and the leeward side of buildings. In the early afternoon there is a characteristic easterly wind which blows across the Lake. The newly emerged gnats come shoreward with this wind and intermingle with the gnats from the previous day. Almost as if by magic a westerly wind comes up between 3 and 4 o'clock and dies down gradually by sunset when the Lake is usually Fig. 1.—Female Clear Lake gnat. The insert sho
. The Clear Lake gnat. Diptera; Diptera. University of California—Experiment Station midafternoon, especially on hot days, the gnats may be found resting on the trees, tules, grass, and the leeward side of buildings. In the early afternoon there is a characteristic easterly wind which blows across the Lake. The newly emerged gnats come shoreward with this wind and intermingle with the gnats from the previous day. Almost as if by magic a westerly wind comes up between 3 and 4 o'clock and dies down gradually by sunset when the Lake is usually Fig. 1.—Female Clear Lake gnat. The insert shows the insect natural size. Just about sundown when the wind has died down, the characteristic hum of the courting males begins and mating takes place as already de- scribed. After sunset an examination of gnats collected along the shore line showed 75 per cent females up to about 10 o'clock, when the males began to predominate. The lakeward migration of the females starts almost exactly 15 min- utes before sundown. It is doubtful whether the females of Chaoborus lacustris continue to oviposit throughout the entire night, since most adult activity ceases with the chilling effect of the late evening breeze. The great activity during the evening leads us to believe that oviposition takes place early. DESCRIPTION OF THE GNAT This gnat was described as a new species by S. B. Freeborn of the Uni- versity of California in 1926 and was named Chaoborus lacustris, being. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Herms, William B. (William Brodbeck), 1876-1949. Berkeley, Cal. : Agricultural Experiment Station
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