1*27 
Reviews and Extracts. — J^atural History. 
vviiicli in butterflies we are accustomed to call the C/iri/mL's (from its golden co¬ 
lour in many of those insects); and before the end of spring', the bark of an 
infected tree begins to appear as if all its crevices were full of a very fine sawdust. 
—The last change of the insect takes place; and being now winged, it endea¬ 
vours to arrive at the external air, for the purpose of 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 se¬ 
cond, the endeavours of the perfect insects to liberate themselves from the wood, 
particularly when such attempts are made by almost incalculable numbers, soon 
occasion the bark to fall in large pieces. The consequence is, that the new leaves 
only make their appearance to wither, and the tree perishes. 
“ Now it is evident from these facts, that the tremendous ravages of these in¬ 
sects,—these small beetles which thus render themselves more formidable to man¬ 
kind, than the strongest and most ferocious beasts of prey, might have been 
prevented, and the evil repressed at its commencement, had the possessors or 
inspectors of the trees been acquainted with the jSatiiral History of the insects ; 
and it is this knowledge alone which could have enabled them effectually to have 
done so. 
‘•We have found that in their perfect state—as winged beetles, the insects are 
the most formidable, having attained the power of propagating the disease from 
one tree to many others. But it is also from an accurate knowledge of them 
whilst in this state, that we can alone derive any hope of being able to counteract 
the mischief they occasion. 
“ The first thing indeed, to be done, in all such cases, is to ascertain the species 
of perfect insect which occasions the disease. The experienced naturalist, from 
an exannnation in this respect of the worm or larvae which he finds devouring the 
timber, is able not only to ascertain the Order and the Family, but often the Ge¬ 
nas, and even the Species of winged insects which have produced it. Thus, in 
the present case, an Entomologist, by certain characters he would see in the lar¬ 
vae, the nature of which his scientific knowledge would point out to him, would 
be able to determine, in the first instance, that the larvae belonged to the Order 
Coleoptera or Beetles ; by others that it belonged to the Family of Beetles, called 
Ptinida’, from that which possesses their characters in the greatest perfection 
being called a Ptinas. By other circumstances he would ascertain that it must 
be referred to that Genus of Pfinidee which bears the name of Hylensius ; and 
lastly, from still more minute examination, he would find it to be the species ////- 
loisias Destritctor, so named from its powers of destruction which we have already 
examined. 
“ Having thus determined the species, or even the genus only, of the insect, 
it becomes an easy matter to the Entomologist to know the season of its appear¬ 
ance. None of the timber-eating insects, his general knowledge of these animals 
informs him, remain alive in their perfect or winged state, throughout the year, 
and they rarely remain so for more than eight weeks. He finds, therefore, that 
we may easily ascertain the exact time for cutting down those trees which are 
so much injured by the larvae as to preclude all hope of saving them ; for it would 
obviously be the height of imprudence not to seize the only opportunity of pre¬ 
venting the annual dispersion of the disease, by destroying the brood of larvae 
whilst yet in the trees As soon as the metamorphosis has taken place,—as soon 
asthe winged insect has made its appearance,—the mischief for the ensuing year 
is done. Time is thus lost, more trees are inevitably destroyed, and, what is an 
evil of far greater magnitude, the future eradication of the disease is rendered 
much more difficult. 
