348 AUSTRALIAN NATIVE PLANTS. 
The lava, hatched from eggs laid in crevices of the bark of the 
branches, works steadily into the interior of the tree, proceeding 
head downwards, enlarging the cylindrical burrows as it gradually 
grows larger and eats its way downwards, often reaching to the roots. 
When about to assume the pupa state it forms a slight cylindrical 
cocoon from four inches to a foot long, of silk and sawdust-like 
small grains of wood, as a lining to the end of its burrow. When 
the burrow terminates in a root a few inches below the surface of 
the ground, the cocoon is continued from the hole in the wood 
upwards as far as close to the surface of the ground; but when 
the burrow ends in the surface of the trunk of the tree above the 
ground level there is no prolongation of the cocoon. In either 
case the pupa works itself forward by means of the little deflected 
spines on the rings, pushing for half-an-inch or so through the end 
of the cocoon before it bursts to allow the imago to escape. 
The ovipositor of the females is of extraordinary length and 
rigidity, equalling half the length of the abdomen when exserted, 
but capable of being entirely retracted out of sight; with this the 
eggs are deposited deep in the crevices or fissures of the bark of 
the trees, on the inner timber of which the larva feeds. 
It is common in the winged state about February, flying in 
the twilight, in all parts where wattle trees abound. 
In most forest-bearing countries the natural enemies of the 
larve, and protectors of the trees, are woodpeckers, who by 
instinct know where the larve are, and by powerful strokes of 
their bills cut down quickly on them through the sound wood, and 
transfixing the grubs with their long worm-like, barbed tongue, 
draw them out, and devour them. In Australia there are no 
woodpeckers, and the consequence is that every tree cut up for 
firewood is seen to be traversed with large cylindrical canals made 
by these or allied larvae, which are the greatest destroyers of our 
forests, so abounding in the wood of almost every forest tree that, 
in a storm, it is dangerous to go near a large tree, as one ap- 
parently sound may snap across unexpectedly with a moderate wind. 
Note-—The heights and diameters given of trees (below 
referred to) must only be received as approximations. The dia- 
meters are those of the stems about three feet from the ground. 
