118 INDIRECT INJURIES CAUSED BY INSECTS. 



of Cnethocampa processioned ; and those of England by the leaf-rolling 

 caterpillar of the pretty little green moth Tortrix viridana. Our elms have 

 their leaves frequently drilled into holes by the little jumping weevil, 

 Orchestes fagi, and the beech, alder, &c., are partially disfigured by other 

 species of this saltatorial tribe. In France, however, the elms sustain a 

 much more serious injury from the larva of another larger beetle (Galle- 

 ruca calmariensis), the leaves being sometimes so covered with them, and 

 rendered so brown, as to have the appearance of having been struck by 

 lightning, as was the case with the fine promenades of Rouen, when I was 

 there in 1836. CheimatoUa brumata is likewise a fearful enemy to the 

 foliage of almost every kind of tree. 1 The woods in certain provinces of 

 North America are in some years entirely stripped by the caterpillar of 

 another moth, which eats all kinds of leaves. This happening at a time 

 of the year when the heat is most excessive, is attended by fatal conse- 

 quences ; for, being deprived of the shelter of their foliage, whole forests 

 are sometimes entirely dried up and ruined. 3 The brown-tail moth, before 

 alluded to, which occasionally bares our hawthorn hedges, has been ren- 

 dered famous by the alarm it caused to the inhabitants of the vicinity of 

 the metropolis in 1782, when rewards were offered for collecting the cater- 

 pillars, and the churchwardens and overseers of the parishes attended to 

 see them burnt by bushels. You may have observed, perhaps, in some 

 cabinets of foreign insects, an ant, the head of which is very large in pro- 

 portion to the size of its body, with a piece of leaf in its mouth many 

 times bigger than itself. These ants, called in Tobago parasol ants (Atta 

 cephalotes), cut circular pieces out of the leaves of various trees and plants, 

 which they carry in their jaws to their nests ; and they will strip a tree of 

 its leaves in a night, a circumstance which has been confirmed to me by 

 Captain Hancock. 3 Stedman mentions another very large ant, being at 

 least an inch in length, which has the same instinct. It was a pleasant 

 spectacle, he observes, to behold this army of ants marching constantly in 

 the same direction, and each individual with its bit of green leaf in its 



their down-covered patch of eggs. In the Park they were also very abundant ; and 

 it may be safely asserted that if one half of the eggs deposited were to be hatched, 

 in 1827 scarcely a leaf would remain in either of these favourite places of public re- 

 sort. Happily, however, this calamity was prevented by natural means. Of the 

 vast number of patches of eggs which I saw on almost every tree in the Park about 

 the end of September, I could two months afterwards, to my no small surprise, dis- 

 cover scarcely one, though the singularity of the fact made me examine closely. 

 For their disappearance I have no doubt the inhabitants of Brussels are indebted to 

 the tit-mouse (Parus), the tree-creeper ( Certhia familiaris), and other small birds 

 known to derive part of their food from the eggs of insects, and which abound in the 

 Park, where they may be often seen running up and down the trunks of the trees, at 

 once providing their own food and rendering a service to man, which all his powers 

 would be inadequate completely to effect. 



Eeaumur (ii. 106.) in certain seasons found these patches of eggs so numerous, that 

 in the JBois de Boulogne there was scarcely an oak, the under side of the branches of 

 which were not covered by them for an extent of seven or eight feet. He informs 

 us that the eggs are not hatched till the following spring. 



1 De Geer, ii. 452. 2 Kalm's Travels, ii. 7. 



5 The same intelligent gentleman related to me, that a person having taken some 

 land at Bahia in the Brazils, he was compelled by these ants, which were so numer- 

 ous as to render every effort to destroy them ineffectual, to relinquish the occupation 

 of it. Their nests were excavated to 'the astonishing depth of fourteen feet. Merian, 

 Insect. Sur. 18. Smeatuman on Termites, Phil. Trans. Ixxi. 39. note 35. 



