INSECTS
is no admixture of the blackened contents of the burrows. It is unlikely, too, that they base their judgments on a sense of temperature, because their acts are not regulated by the nature of the season, which if early or late, would fool them in their calculations.
Early in the spring, before the proper emergence season, cicada nymphs are often found beneath logs and stones. This is to be expected, for, to the ascending insect, something impenetrable has blocked the way, and there is nothing to tell it that it has already reached the level of the surface.
A more curious thing, often observed in some localities,
Fig. 117. Earthen turrets sometimes erected by the nymphs of the periodical cicada as continuations from their underground chambers. One cut open showing the tubular cavity within. (From photograph by Marlatt)
is that the insects sometimes continue their chambers up above the surface of the ground within closed turrets of mud from two to several inches in height. (Fig. 117). At certain places these cicada "huts" have been reported as occurring in great numbers; and it has been supposed that they may be built wherever there is something about the nature of the soil that the insects do not like, the earth perhaps being too damp, for they are frequently found where the ground is unusually wet. On the other hand, and towers and holes flush with the surface frequently occur intermingled. The writer has had no opportunity of studying the cicada turrets, but a most interesting description of them is given
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