Whenever she leaves her nest she makes three or four rapid circles around the spot to freshen her memory of the locality. The most thorough study that we saw made by clypeata was in the case of the wasp mentioned before, that was so long in carrying her beetle in because of our being on the ground. When she finally did go in she stayed only an instant—just long enough to deposit her load—and then came out and spent a long time in an investigation of all the surrounding objects, flying in and out among the plants, now high, now low, and circling again and again around the spot. It looked as though she had been puzzled and disturbed by the presence of unaccustomed things. As soon as the survey was over she went inside and closed the door, as though its object had been not so much to strengthen her memory as to correct former impressions.
The work of bringing in beetles goes on very irregularly, and as a rule not more than two or three are stored in the course of a day. It is not unusual for clypeata to spend three or four hours away from home and then come back without anything; and often, even in the middle of the day, she passes an hour or two in the seclusion of her nest. We had several nests under observation for a week at a time without ever once seeing the owners, although they were evidently occupied, since they were sometimes open and sometimes closed. The outer entrance is always left open when the wasp goes away, although possibly access to the pockets may be barred below; but when she enters she closes the door unless she means to come out again at once. The closing is sometimes effected by pushing the earth up backwards, with the end of the abdomen; but the hole is rather too large for this method, and more frequently the wasp comes up head first, carrying a load of earth in her front legs. This is placed just within and to one side of the entrance, and then more armfuls are brought up, until, after two or three trips, the opening is entirely filled.
We once captured the wasp in a bottle, as she returned, loaded, to the nest. She dropped the beetle, but soon picked it up again and stung it vigorously, _with intention_, as the French say, first under the neck, and then further back, behind the first pair of legs. After this it was dropped while the wasp fluttered about for a few minutes, but it was then picked up again, and stung as before. We both saw this operation repeated in exactly the same way, four different times, with intervals of five or six minutes between.