126 
Reviews and Extracts. — J^atural History. 
the same period, the Elms in the Grove at Cainherwell, near London,—a place 
consecrated in tlie memory of many persons, by havings been the residence of the 
late philanthropist. Dr. Lettsoin—were observed to be underjvoing' a similar pro¬ 
cess of destruction ; and the proprietors being equally ignorant of its cause, as in 
the instances I have just mentioned, the injury was ascribed to the effects of gas, 
escaped from the pipes for lighting the road, which had just been laid down j and 
legal proceedings were actually commenced for the removal of this nuisance, 
against the Gas Company which had undertaken the supply. 
“ Entomologists, it is true, had long been aware that the operations of insects 
were the cause of all this mischief j unfortunately however, they were not believed 
until the disease had reached that pitch, which threatened to make remedy hope¬ 
less. It was evident to those acquainted with the subject, that unless decisive 
measures were soon taken to resist the progress of the contagion, it was to be ex¬ 
pected that not only every tree of this species in the Parks would be destroyed, 
but that the evil would be disseminated throughout the vicinity of the metropolis, 
to several plantations on the north of which, it had already extended. 
“In this stale of things, Mr. William Sharp Macleay, an eminent Naturalist, 
profoundly acquainted with the history of Insects, was requested by Lord Sydney, 
the Ranger of the Parks, to draw up a report on the state of the Elm-trees in 
them, for the purpose of referring it to the Lords of the Treasury. 
“ In this Report, Mr. Macleay shows that all the havoc had been committed by 
a species of Beetle, belonging to the same natural family as that which destroyed 
the Pines in Germany; and not more than one-sixth of an inch in length, called 
the Hylensius Deslructor, or Destroyer Hylensius. 
“It appears further from the Report, and from other axithentic sources, that 
from the middle of March to September, but principally about the end of May and 
the commencement of June, this insect, distinguished by its polished black head 
and thorax, the head thickly covered with hair, and its brown wing cases, may 
be seen in numbers, running over the trunks of the Elms, This is the animal in 
its perfect state. It may be seen also, entering into holes, with which (he bark 
appears perforated as though with a gimlet j it insinuates itself into the holes, or 
into the crevices of the bark, for the purpose of depositing its eggs. On strip¬ 
ping off a piece of the loose bark, we may easily at any sea.son understand how 
the barking of the trees is effected by these minute animals ; for the surface of the 
wood thus exposed, presents to the view innumerable impressions, or excavations, 
each consisting of a comparatively wide middle trench, with others much narrower, 
extending from it at right angles, but in a parallel direction to each other. 
“ The middle or body of this singular impre,ssion, is the passage which has 
been formed between the bark and the wood, or rather within the thickness, to a 
certain extent, of both, by the female insect, depositing her eggs, on each side, in 
her course , until she is exhausted of them, when she dies, and may accordingly 
generally be found at the extremity of the channel; the deposition of her eggs 
being to her, as to most other winged insects, the immediate forerunner of death. 
From this tubular path, however, the larvae which are hatched from these eggs, 
deposited very close to each other, in the shape of little white worms or grubs, 
destitute of legs, proceed nearly at right angles, eating their way in smaller tubes 
parallel to each other, which lying close together, serve effectually to separate 
the bark from the tree. The larvae remains feeding in the tree, generally in this 
situation throughout the winter. During tfiat season, the sap of the tree being 
down, the bark adheres less firmly, the grubs work with greater facility, and the 
mischief is consequently augmetited. About the commencement of spring, they 
assume the Papa or Nymph stale—that condition or stage of their metamorjihosis 
