on various Species of Hymenopterous Insects. 139 
3. Some account of the Habits of a new Species of fossorial Hyme- 
nopterous Insect from South Australia. ByJ.O. Westwoop. 
[Read 3d January, 1842.] 
Tue various modes employed by the nidificating aculeated Hy- 
menoptera, in the construction of their nests, and the adaptation of . 
their structure to the purposes of their economy, in this respect 
afford materials for observations of the most interesting as well as 
instructive kind ; interesting, from the singularity of the manceu- 
vres and assiduity of the insects; and instructive, from furnishing 
us with complete details of the history of particular species, there- 
by confirming, in the most satisfactory manner, their relations 
with other species. The nest-making Aculeate may be divided 
into several distinct groups, from the mode of construction of 
their nests. Not to speak of the social kinds, which form beautiful 
structures composed of series of hexagonal cells, or of the social 
humble bees, we find the solitary nidificating species again divided 
into such as merely content themselves with making a burrow 
in rotten wood, or in a sand-bank, in which they bury a caterpillar, 
or other insect or spider, and those which fetch the materials of 
their nests from a distance, which they then either employ as a 
lining to their burrows, or else form into an exposed nest, without 
previously forming any burrow. 
In our own country I believe no fossorial species exists which 
forms exposed nests, all the species (except the parasitic ones) 
possessing an economy, which is indicated by their name of Fos- 
sores. Some of the species, indeed, as well as some of the wasps 
and bees, fetch materials from a distance to line their celis, already 
formed in burrows; a few of the bees however (such as Megachile 
muraria) form naked nests on the surface of walls, &c. The exotic 
genus Pelop@us is the only recorded instance of a fossorial insect 
making an external nest. 
The nests which, with their inhabitants, form the subject of the 
present communication, were brought from Port Lincoln, South 
Australia, but unaccompanied by any details. They are however 
evidently nests formed externally, in the same manner as the nests 
of the Megachile muraria. They came to me in several masses, 
each consisting of two or three cells; each cell is about an inch 
long, and half an inch in diameter ; they are smooth on the inner 
surface, and the case is about the thickness of the shell of a hazel 
nut, with the outer surface very rugose, as though formed of a suc- 
cession of short transverse layers, which have dried into rounded 
