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Page:Popular Science Monthly Volume 61.djvu/354

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348
POPULAR SCIENCE MONTHLY.

that is, to fly, and, if flight takes it back to the nest, the rest of the procedure is probably carried out. Repetitions of this chain of actions causes it to occur oftener and with greater constancy, until the habit in all its complexity is well established.

It is well known that usually the wasp flies straight out from the nest, and does not return by the path it took in leaving. And while it appears that the first 'locality studies' are the desultory wanderings just described, there are nevertheless circumstances where Polistes makes the swift survey of the objects surrounding her nest, which has been described by Mr. and Mrs. Peckham for many of the solitary wasps. I observed this in numbers of instances where the wasps were set free after having been left in captivity long enough to habituate themselves to their new surroundings.

One nest with four workers was brought into the laboratory and established in a large glass cylinder, with a supply of food and weather-worn wood, so that they might go on with their activities if so inclined. They soon ceased their attempts to escape, and by the end of a week were attending to the wants of the larvæ in the usual manner. The glass plate from which the nest was suspended, was then moved to one side so as to leave an opening of several inches, but the wasps not perceiving this after several trials, the whole was carefully lifted out and rested on two supports, so that the wasp would find itself free if it flew six inches in any direction. Following is an account of a typical locality study transcribed from my notebook:

11:10. Freed nest (way already indicated). One of the wasps has flown out from the nest, hovers above it at a distance of twelve inches, and rising to the ceiling hovers there for some seconds. During the next six minutes descends to hover and circle within six inches of the nest, and, a second time, comes within two inches, without, however, alighting on it. First, flies round with its head directed toward nest, then turning, circles with its head away from the nest. This performance is repeated, and at 11:10 it alights on the glass, from the under side of which the nest is suspended, and for twenty seconds it beats its head against the glass. Rising, it explores first the upper, then the middle section of the room. Rising to the ceiling once more, hovers there and then descends to rest on glass as before. Spends several minutes exploring the room, and, returning, hovers for a few seconds before dropping upon the nest.

This is a fairly representative procedure, though there is great individual variation in the number and character of the circlings and the amount of search necessary in finding the nest after the more distant parts of the room have been visited.

Although no lengthy series of experiments was carried out with the same individual, those that were made show a decrease in the number and minuteness of the circlings proportional to the number of times the wasp so left the nest. The wasp never returned to the nest along