126 Mr W. S. Macleay on the State of the Elm-Trees 
of May or commencement of June. It may then be seen enter, 
ing into holes, with which the bark appears perforated as though 
with a gimlet. It insinuates itself into these holes, or into the 
crevices of the bark, for the purpose of depositing its eggs. On 
stripping off a piece of the loose bark, we may easily at any 
Season understand how the barking of trees is effected by these 
minute animals, for the surface of the wood thus exposed pre- 
sents to the view innumerable impressions, which may be com- 
pared to impressions or casts of large and broad scolopeh- 
drae. 
The middle or body of this singular impression * marks the 
path of the perfect female insect, while employed in laying her 
eggs, which is to her, as to most other winged insects, the im- 
mediate forerunner of death. From this tubular path, however, 
in which she deposits her eggs, the larvse, which are hatched 
from these eggs, in the shape of little white apod worms, pro- 
ceed nearly at right angles, eating their way in parallel smaller 
tubes, which, lying close to each other, effectually serve to se- 
parate the bark from the tree. The larvae remain feeding in 
the tree, generally between the bark and the wood, throughout 
the winter season. About the commencement of spring they as* 
sume the pupa or nymph state, and, before the end of this sea- 
son, the bark of an infected tree begins to appear as if all its 
crevices were full of a very fine saw-dust. The last change of 
the insect takes place ; and being now winged, it tries to arrive 
at the external air, for the purpose of propagating its species, and 
laying its eggs in other trees. Each hole which now appears as 
if made with a gimlet, marks the exit of a perfect insect. In 
the first instance, the voracity of the larvae, and, in the second, 
the endeavours of the perfect insects to liberate themselves from 
the wood, particularly when such attempts are made by almost 
infinite numbers, soon occasion the bark to fall in large pieces. 
The consequence is, that the new leaves only make their appear- 
ance to wither, and the tree perishes. 
The early entomologists, little acquainted with metamor- 
* Impressions of a similar nature, when made on the wood by insects of a 
neighbouring genus, have given rise to such trivial names as typographus , micro - 
graphusy &c. with which the entomologist is so familiar in the genus Bo$tricku$> 
