224 
Psyche 
[Vol. 87 
Pison ignavum Turner 
This is a widely distributed species in the Australian zoogeographic 
region. Williams (1945) found that in New Caledonia this species 
“constructs free cells of mud pellets and sometimes hangs them from 
rootlets exposed in a bank". We collected a nest plastered to the 
underside of a Banksia leaf overhanging a stagnant pool a few meters 
from Blunder Creek, Brisbane, in Eucalyptus-Melaleuca woodland, 
not far from the first nest of P. rufipes, cited above. This nest was 4.5 
cm long, 3.1 cm wide, and 0.8 cm deep; it occupied about a third of the 
area of the leaf (Fig. 4). Seven cells could be faintly discerned beneath 
the lumpy surface of gray mud. This nest was collected in late 
November, 1979; about a month later 5 P. ignavum emerged, each 
leaving a small hole about 3 mm in diameter. 
Pison westwoodi Shuckard 
This very small species was reported above as having been reared 
from a nest of P. rufipes, where it had possibly usurped some cells or 
added cells to a completed nest. Evidently it utilizes various pre¬ 
existing cavities, as we also reared the species from three trap nests set 
up near Canberra, Australian Capital Territory, in December 1969 
and February 1970. All three trap nests had a bore diameter of 4.5 
mm, the smallest bore employed. A nest set out near the Murrum- 
bidgee River had three cells, 9-14 mm in length, separated by mud 
partitions 1-2 mm thick; these were separated from the entrance to 
the boring by a long, empty cell, which was closed off by a thick mud 
plug. The cells contained cocoons when collected, and these gave rise 
to three adults the following spring. The second nest, on the window 
ledge of a house in Canberra, contained seven cells, varying in length 
form 6.5 to 12.5 mm. All contained larvae and the remains of spiders 
when the nest was collected in mid-December; several adult wasps 
emerged in late January. 
The third trap nest had been set on top of a fence rail not far from 
the preceding. It was sealed in mid-December and opened on 28 
December. There were four cells, 6.5-12.5 mm in length, separated by 
thin mud partitions. The two innermost cells contained many tiny 
spiderlings, 19 and 30 per cell; evidently the egg had failed to hatch in 
these cells. The two outermost cells contained cocoons, one of which 
gave rise to a male on 27 January. Cocoons of this species measure 
