30 Observations on an Australian Mud Dauber etc. 
the cells may vary considerably in shape. The second cell was nearly completed 
at 10.51 a. m. but it lacked the rim or neck of the entrance. This was completed 
at 11.14 a. m., and the wasp then flew off. This second cell was broader and 
shorter than the first, shaped more like a loaf of bread, somewhat longer than 
wide and with the ends of the longer axis more or less truncately rounded off. 
Thus, even the individual cells made by the same female may vary considerably. 
When leaving, after completion of the cell, the wasp flew off in a direction 
divergent from that of the regular flights during building. 
She had not returned by noon but at 1.30 p. m. it was noticed that at 
least one caterpillar had been added to the cell; it remained open during the 
rest of the day and the following night. A second caterpillar was added at 
11.30 a m., June 20 but I did not see others added and the cell again remained 
open during the night (the day was windy and cloudy, rather cool). On June 21, 
the mother wasp was first noticed at 10 o’clock; she was on the nest and was 
frightened by my movements near the nest remaining „alert“ and still for some 
time. After she left, I could not see that anything had been added to the second 
cell. At 4.20 p. m. the latter was found to have been closed and a third begun, 
above and against it. Only the two end sides were built up in the shape of 
crescents; the female had stopped work for the day. June 22 was rainy, windy 
and chilly and no work was done. June 23 at 4 o’clock, I found that the third 
cell had been completed, though the day was rainy throughout, except for short 
intervals near noon. The cell was empty. June 24 was clearer, fair and warm; 
the moiher wasp was observed to put a caterpillar in cell 3 at obout 10 a. m; 
she paid it out through her iore legs, using the mandibles as formerly observed. 
Another caterpillar, which filled the cell, was added at four o’clock and soon 
afterward the cell was capped 
At 4.20 p. m., it was noticed that a fourth dell had been commenced above 
the third, the end walls raised first, at that time not very high. At 5.35, she was 
still at work on cell 4 which was nearing completion; at this time, she was visi- 
ting an entirely different spot for building material. Cell 4 was not quite com- 
pleted today but at 8.30 the following morning (June 25), it was finished excep- 
ting the neck; later, it was found that the latter was not added, the round en- 
trance hole merely being slightly rimmed, not a distinct flange as usual; this is 
another variation. By 10.15 a. m. June 25 a caterpillar had been added to cell 4. 
A fiith cell was constructed between 2 and 5 p. m. June 25, with the usual 
neck but the latter not so large as usual. This cell remained empty and open 
during the night following but was filled the next day and closed about 6 p. m. 
On June 27 at 8.40 a. m., the female began a sixth cell above and against cell 
5; all six cells are in a single row against the wooden joist, side to side. Cell 
6 was completed by 10 a. m. (at least; not actual time). At 3.30 p. m. June 28, 
cell 6 was found to have been recently closed and a seventh cell partly con- 
structed beside and against it. When completed, this cell had no rimming at 
all about the entrance. It was left open during the night though it contained 
at least one caterpillar; the wasp was not on or near the nest at IO p. m. and 
evidently spends the night elsewhere At 2 p. m. June 29, the seventh cell was 
found to have been closed (since I p. m.) and an eighth begun above it and 
against the joist, as with the others. This cell was completed by 3.30 p. m. or 
sooner and had no rimmed entrance. By 4.40 p. m. it was full but nevertheless 
was leit open during the following night (the wasp being absent). During the 
following morning it was closed; unlike the Sceliphron, this wasp does not close 
its partly filled cells before leaving the nest for the night; the day_of June 30 
was occupied in building a ninth cell which was stocked and closed by 6 p. m. 
(at 4.30 p. m. it had only been partly stocked); this cell was against and above 
cell 8. July 1, the mother wasp continued building whenever the rain ceased, 
completing a tenth cell above and against cell nine; she commenced to work at 
about 8.30 a m.; cell 10 was completed at about 3.30 p. m.; it had no rim about 
the entrance. It remained open (and empty) during the night and was filled 
during the morning of July 2 and closed at 10.45 a. m. After this, the female 
wasp daubed pellets of mud over the nest for a short while and then began an 
eleventh cell above the tenth and still in the same place; this cell was finished 
at about I p. m. and though partly filled during the afternoon it was left open 
the following night (with untoward consequences as we shall see). At 8.30 a. m. 
July 3, the open eleventh cell was found to have been invaded by ants (this 
doubtless explains why Sceliphron cementarius closes its partly filled cells at night, 
