208 Rev. G. A. Crawshay on the 
propagation of the insect. Another very important factor 
is the remarkably short life cycle. 
While one brood of the slower-developing Longicorns 
such as Criocephalus is being perfected, many generations 
of Tetropium will have emerged and spread among sickly 
trees, which they will quickly kill and desert. 
The GREEN WOODPECKER, Gecinus viridis, renders 
affected trees very unsightly by hammering innumerable 
large holes in the bark with its bill to extract the larva 
and pupee. 
DamacE To TimpeR.—lIt is quite certain that the species cannot 
injure healthy trees. Whether it lays upon these through lack of 
discrimination or not I cannot say. In the event of its doing so the 
newly-hatched larva must inevitably be smothered in its minute 
burrow by the flow of sap on eating into the surface of the tender 
bark. I have only found the larva in failing trees. 
From a commercial point of view the species injures the wood to 
a certain extent, but considerably less than Criocephalus and Sirex, 
which feed in the wood itself, excavating it more deeply and toa 
much greater extent. 
METHODS OF REARING THE Larva—The methods I 
adopted were as follow :— 
As the habit of the larva is to feed over the smooth, 
sappy surface of the wood cylinder and upon the inner- 
most lining of bast adjacent to it, it occurred to me to 
substitute glass for the wood surface, and, placing the 
inner surface of the tender and pliable bark against it, 
insert the newly-hatched larva between them. It might 
thus be induced to feed next the glass and admit of being 
observed continually. 
No. 1.—Accordingly I fitted a ring of fresh, tender bast, 
separated from the outer dead bark and therefore pliable, 
firmly and closely to the inner surface of a 3-in. corked 
glass tube of equal dimensions from the rim throughout 
(such as appear in Plate XIX, «a, b,c, d), and inserted the 
larva in a fine groove, little more than a pin-scratch, made 
by drawing the head of a small pin down the bark, and 
extending an inch or more downwards from the rim of 
the tube. A V-shaped opening to this tiny groove was 
made at the rim, to start the larva in, for it cannot be 
inserted in the very small groove itself without injury, but 
must make its way in. The cylinder of bark had previously 
been pressed tightly to the glass by filling in the empty 
