110 THE AUSTRALIAN NATURALIST. 
The outer tunnels shown in the eross section photograph 
are not continuous. They are worked as follows:—The larvae 
worked in horizontally or obliquely for an inch or an inch and 
a half, worked downwards for a few inches, then worked to the 
surface of the inner bark again. Here they rest awhile until 
they are ready to bore in once more. Then they return to their 
little recess and continue their journey downwards, coming to 
the surface at intervals of varying lengths. Other excavations 
showed that the larvae on coming to the surface did not continue 
the old tunnels, but bored in an entirely new place, going in, 
down and to the surface again as described above. Then, again, 
I found that other holes extended in for only an inch or two and 
stopped. These methods of working would explain the reason 
why the bole is so studded with holes, and yet the cross section 
shows so few. 
The inner tunnels shown in the photograph are continuous, 
and were made by the more mature larvae; these make long 
tunnels and pupate at the end of them. I traced their tunnels in 
for four or more inches, then down for two feet. Had the tim- 
ber been cut in longer lengths, undoubtedly, I would have found 
them continue much longer. One enterprising larva tunnelled 
into the heart of the tree. 
The cutting down of the tree evidently shortened the larva 
stage of those concealed in the tree. Through their food supply 
being cut off they were forced to pupate. This they did close to 
the top of the tunnels in the cut timber. Unfortunately, I only 
became aware of this fact through poking out the tunnels to test 
their length. I found, however, that they were an inch and a 
half long, and adhered to the sides of the tunnel. 
The moth is a slate grey colour with fine black markings all 
over its wings. 
CALLITHAMNION PLUMIGERUM. 
By Tuistte J. Harris. 
This is a very delicate -feathery seaweed, one of the most 
beautiful of our Australian types. It is classed amongst the 
Ceramiales of the Rhodophyceae (Red seaweeds). It may be 
seen growing on rock platforms and in tide pools where it is 
never left entirely exposed. Microscopic examination shows that 
it is made up of a series of relatively thick-walled cells with the 
cytoplasm somewhat contracted from the walls, that of each cell 
