228 
Psyche 
[Vol. 87 
February had larvae in all cells, the larvae being progressively smaller 
toward the entrance. The spiders in this nest appeared very diverse, 
but were not saved. The other three nests, collected 10 February-26 
March, contained nothing but cocoons aside from three cells in which 
the egg had evidently failed to hatch; these contained 5-6 spiders 
each, all of them Cymbacha festiva Koch (3 $$, 1 13 immatures) 
(Thomisidae). Cocoons of this species measure 11-13 mm in length 
and are quite different in form frc/m those of the preceding three 
species, being abruptly widened at the anterior end (Fig. 10). 
Although our specimens key readily to tibiale in Turner’s (1916) 
review, our impression is that several species are now being confused 
under that name. Our voucher specimens, in the Australian National 
Insect Collections, Canberra, should enable our material to be 
associated with the correct species name when a much-needed 
revision of the Australian species is available. 
Discussion 
The Australian species of the genus Pison evidently fall into three 
discrete groups with respect to nesting behavior. Members of the first 
group build free mud nests consisting of several cells attached to 
stems, roots, or leaves and coated with mud in such a way that the 
cells are not individually discernible on the surface. The two species 
rufipes and ignavum belong to this group, and it is noteworthy that 
both belong to a species-group in which the second recurrent vein is 
received at the middle of the second submarginal cell, rather than 
near its apex as in most Pison species. The prey of rufipes was found 
to consist of Salticidae. 
The remaining species considered here (westwoodi, spinolae, 
marginatum, and sp. nr. tibiale) all accept hollow,^ubular trap nests, 
although there is evidence that the first two are somewhat more 
versatile in their nesting behavior. Cells are separated by thin mud 
partitions and the nest is often closed off with a thick mud plug. These 
species appear to make extensive use of orb-weaving spiders, most 
records being for Araneidae, although there is one record for 
Oxyopidae and several for Thomisidae. The cocoons show interest- 
ing species differences, not unlike those found among North 
American species of the related genus Trypoxylon (Krombein, 1967; 
Matthews and Matthews, 1968). These cocoon differences are 
summarized in Table I. 
