Observations on an Australian Mud Dauber etc. 31 



reopening them the next morning) which were attacking the inclosed cater- 

 pillars; shortly, the wasp arrived at the nest (I did not see her behavior upon 

 arrival), closing the etrance of the cell at once (hardly. I think saving its Con- 

 tents, because some of the ants were most probably shut in and would be quite 

 capable of destroylng what was left) and then daubing pellets of mud over the 

 line of ceils, continuing ihls up to noon (thus this disturbance by ants, at once 

 stimulated the instinct of seif preservation; the wasp discontinued her building 

 Operations at once and made efforts to insure the safety of the progency already 

 provided for) and through the afternoon up to 5.30 p. m., July 4, as early as 

 8.30 a. m., the mothes wasp was at work, continuing to cover the „flat" row of 

 cells with earth until noon. 



At this time, 1 distinctiy saw her make two trips to a spot beneath the 

 verandah and gather dry earth, applying it each time to a dry place on the nest; 

 yet when these spots were examined after the female left, they were wet and 

 pliable and therefore the female must use some sort of saliva. Consequently, 1 

 went below to the spot which she was visiting and saw her make six successive 

 trips to it; after each trip, I examined the exact spot from which she had been 

 gathering and at each place there was a small round concavity made by the 

 mandibles perfectly wet. But, under each of these it was dry and aflerward I 

 dug up with my knife all the earth near the spot and under it without encounte- 

 ring moisture above the depth of two inches; the nature of the earth was sandy. 

 The wasp was gathering sand from one little area which had become a grooved 

 semicircle. Within an area of several Square feet at this place were many of 

 these shallow cavities, most of them quite irregularly situated but at this time 

 this wasp was visiting one particular spot where her gathering Operations had 

 iormed one of these cavities as noted, a shallow groove, crescentic in shape and 

 resembling one which would be formed by drawing the tip of the middie finger 

 gently over the sandy ground for a short distance and semicircularly. When the 

 wasp was away at the nest, after her second trip during this Observation, I ob- 

 literated the individuai, small pits making up the grooved semicircle (and made 

 by the mandibles at each gathering) by gently drawing the tip of a finger through 

 tinem; when she returned her actions denoted that she sensed a ditference — 

 she hesitated and turned aside several times before finding the spot; this 

 was repeated on her sixth return, immediately before which I had excavated 

 the groove down to some distance with a knife. This did not disturb her much, 

 however, as after a few seconds she gathered the pellet of sand from one edge 

 of the little excavation. Hence. this species has developed a habit of using her 

 own saliva for the purpose of wetting the pellets of earth used in building Ope- 

 rations, an extremely useful adaptation in a country where (at least before the 

 white man's settlement) much time may elapse at one particular spot before a 

 suitable mudhole could be found or elsewhere it would be necessary to restrict 

 reproduction to the vicinity of permanent watercourses. 



This mother wasp continued to daub over her nest with earth pellets for 

 a while in the afternoon but left later; she was still visiting the dry spot beneath 

 the verandah (a soft muddy spot was not thirty feet away in the roadway). At 

 11 a. m., July 6 she returned and daubed the nest Cluster for a short while, soon 

 leaving. It was not seen again until 11.30 a. m,, July 9, when the nest was daubed 

 intermittently for an hour or two. 



1 was absent until July 31. I was informed that the nest remained unchanged 

 until the day before my return when the nest had heen broken off On the 

 morning of July 31 I found that the eight upper cells had fallen to the floor of 

 the verandah in one piece; these cells were empty but all were lined with silk, 

 showing that they had contained grown larvae; this was probably the work of some 

 bird. I removed the remaining three cells (1, 2 and 3), all of which contained pupae, 

 enclosed within stiff but very thin, white cocoons; the pupa of cell 1 was colored 

 considerably, the others pale. The adult of cell 1 emerged on August 6 at noon; 

 by this date, the two other pupae were more colored and fully so on August 12, 

 emerging on August 14, 1912. 



The following significant facts were observed. 



(1). Variation in the Situation, arrangement and form of the cells is usual 

 and common. 



(2). The mother wasp has not learned that a partly filled cell left open 

 during the night is a source of danger; at any rate, that it would be more 

 economical to close it, even if the egg is not placed in first. 



