m 
in St James's and Hyde Paris. 
phosis, on finding the perfect Hylesinus destructor (le Scolyte of 
Geoffroy), on dead or dying trees, erroneously considered their 
disease to be the cause, and not to be the effect of the insect’s ap- 
pearance. Hence the habitat of this species, in many of the 
older entomological works is said to be rotten wood . The ab- 
surdity of this notion will, however, be obvious, on the slightest 
investigation of the evil, in its earlier stages. It is, for instance, 
allowed on all hands, that the tree perishes by being barked ; 
and the mere inspection of any of the trees so barked, will suf- 
ficiently shew that the mischief is effected in the manner above 
stated. In order to prove that experienced naturalists are now 
aware of the true cause of such vegetable diseases, it may be 
sufficient for me to cite, from the third volume of M. Cuvier’s 
Regne Animal, the prefatory remarks of M. Latreille on the 
whole family of insects to which the Hylesinus destructor be- 
longs : “ Les Xylophages vivent presque tous dans le bois ; 
les larves percent ou y creusent des sillons en divers sens ; et 
lorsqu’elles sont tres abondantes dans une foret, particuliere- 
ment dans celles de pins et de sapins, elles font peril* en peu 
d’annees, une grande quantite d’arbres, ou les mettent hors d’etat 
d’etre employes utilement dans les arts.” 
On a review of the above remarks, it seems, in tire first place, 
advisable for those persons who have elm trees in the state of 
tlrose in the Parks, to inspect them twice every year, first, in sum- 
mer, when the perfect insect is on wing ; and, secondly, in win- 
ter, when those trees which are much infected ought to be cut 
down. Such trees ought, if possible, to be burned with the lar- 
vae in them, or if this be not convenient, they should immediate- 
ly be subjected to such heat or fumigations as may destroy the 
larvae, which at this season are near the surface, and therefore, 
not so difficult to kill. To rest content with having cut down 
the trees, without destroying the larvae, or even removing the 
trunks from the vicinity of the sound wood, is, in reality, to do 
no good at all. 
It may also be recommended, that no more elm-trees be, du- 
ring the continuation of the disease, planted in places where it 
is prevalent. The Hylesinus destructor is peculiar to the elm, 
and was in all probability introduced into the Parks, with some 
