64 THE AUSTRALIAN NATURALIST, 
shorter. The abdomen is slender, orange-coloured, tipped 
with black. A good figure can be seen in Mr. Froggatt’s 
Australian Insects. 
The eggs are round and nearly black, and are about 
the size of radish seed. 
The larva is a long, slender brown grub, with orange- 
coloured transverse bands on the back. When hatched, it 
starts eating its way into the tree. While doing this it 
covers itself over with a felty covering made from the 
bark chewings and a little silk which it spins. This pro- 
tects it from the ravages of other insects, and also keeps 
the water out of its tunnel in wet weather. It tunnels 
down the tree from nine inches to a foot, and then works 
up and down, eating the tunnel larger as it develops, un- 
til the hole is large enough to admit a man’s finger. When 
fully developed in this stage, it draws all the felty cover- 
ing in, and with the aid of a little more silk, makes a cap 
like a thick felt gum wad, which fits so closely into its 
tunnel that nothing else can get in. The development of 
the larve takes two years, and in some cases it may take 
more; but in several cases I had under observation they 
developed in two. When they enter the pupal stage they 
can move up and down freely in their hole by means of 
rings of spines on each segment. 
When fully developed, the pupa. works its way up 
and pushes the wad out, and there rests with the head 
protruding until the shell breaks at the thorax and lets 
the mature moth emerge. This always happens late in 
the afternoon, and they hang there by the front legs un- 
til the wings have expanded. By this time night has 
come on, and they fly off, and are rarely seen again. Pos- 
sibly on account of their size a good number of them fall 
victims to night flying birds. 
A good number of the larvee are also killed by a white 
fungus, if too much moisture gets into their tunnels in 
wet weather. Although great provision is made against 
it, these large moth grubs sometimes fall victims to para- 
sitic wasps. 
THE SPIDER: BUILDER, ENGINEER, AND 
AVIATOR. 
This was the title of a lecture delivered by Mr. W. 
J. Rainbow, F.E.S., on Tuesday, July 6, at the Royal So- 
ciety’s House. This lecture had been previously delivered 
