1 26 Reviews and Extracts. — JVatural History. 
tlie same period, the Elms in tlie Grove at CaiiibervvcU, near London, — a place 
consecrated in the memory of many persons, by having been the residence of the 
late philanthropist, Dr. Lettsom — were obsrrved to be undergoing' a similar pro- 
cessof destruction ; and tht" proprietors being equally ig;norant of its cause, as in 
the instances I have just mentioned, the injury was ascribed to the effects of g-as, 
escaped from the pipes for lighting the road, which had just been laid down ; 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 ; 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 prog-ress of the contagion, it was toTTe fex- 
pected that not only every tree of this species in the Parks would be destroyed, 
but that the evil would be dis-^euiinated throughout the vicinity of the metropolis, 
to several plantations on the north of which, it had a'ready extended. 
"In this state 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 leng-th, called 
the Hylensins Des'r:ictor, or Destroyer Hylensius. 
"It appears further from the Report, aud from other authentic 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 i)olished 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 the bark 
appears perforated as though with a gimlet ; it insin\iates itself into the holes, or 
into the crevices of the bark, for the purpose of depositing its eggs. On strip- 
ping oft" a piece of the loose bark, we may easily at any season 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 impression, 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 iuimediite forerunner of death. 
From this tubular path, however, the larva; which are Imtched from these eggs, 
deposited very close to each other, in the shape of little while 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 larva; remains feeding in the tree, generally in this 
situation throughout the winter. During that season, the sap of the tree being 
down, the bark adheres less firmly, the grubs work with greater facility, and the 
mischief is consequently augmented. About the connnencement of spring, they 
assume the Pupa or Nymph slate — lliat coudition <n; singe of their metamorphosis 
