At another time we took fourteen wasps from the nest of a different species and carried them seventy–three yards to the southeast. The cage was opened so that they could fly out in any direction they chose, and they all started in a straight line for the nest. Later on the same day, we took forty–five from this nest, and set them free one hundred and seventy–six yards to the south. Seven flew north toward the nest, twenty–one south, eight west, and seven east, while the other two circled around as they rose higher and higher, until they were lost to view. None in this experiment returned to take a fresh start.
Again, we took twenty–three wasps three hundred yards southeast of the nest and liberated them in an open field; thirteen flew east or south away from the nest, seven west or northwest toward the nest, and four returned to the starting–place and seemed unwilling to venture out again.
These observations show that the two species of wasps with which we experimented have no sense of direction in the form of a mysterious additional sense, nor yet in the form of a power by which they keep a register of the turns and changes in a journey and are thus able to retrace their way. Our cage was of wire, and so open that they could see all about, as we carried them from place to place; yet when they flew out, they most frequently started in a wrong direction and toward a point that we had not passed. In many instances, however, these wasps returned to the nest, and it seems highly probable that as they rose higher and higher into the air, circling as they went, they discovered some lofty treetop or other object that had before served them as a landmark, and that in this way they were able to make their way home. Bee–keepers know that if young workers which, in strong hives, pass the first ten or fifteen days of their lives in feeding the larvæ without going abroad, are taken out and set free only a short distance from home, they are unable to find their way back, and perish, while those that have passed beyond the nursing stage and have begun to do outside work may be carried long distances away and still readily regain the nest.
With the solitary wasps we attacked the problem from the other end. We observed what the social wasps did in attempting to return to the nest; with the solitaries, we watched them when, after making the nest, they prepared to leave it to go out into the fields or woods in search of food or prey, thinking that the procedure of different species under these circumstances would afford a clue to the faculty upon which they depended to find their way about. If they were furnished with an innate sense of direction they would not need to make a study of the locality of the nest in order to find the way back, but if they were without this sense it would be only common prudence to take a good account of their bearings before going far afield.