ISIS 



AKBORETUM AND FRUTICETUM. 



PART III. 



sanguineus, [n the Magmme of Natural History (iv. p. 2(5,5.), Mr. Dale states 

 thai he found the latter insect " in plenty, both in larva and pupa, on rotten 

 oak stumps, in the New Forest Tillus unifasciatus and ambulans also feed, 

 in the larva State, on the rotten oak; and the latter was captured and bred 

 by Mr. Dale. (See Mag. Nat, Hist., iv. p. 266.) But the most destructive 

 insects to oak timber are the species of the family Lymexylonida?, which, 

 although common in Sweden and some other parts of the Continent, are, 

 fortunately, of great rarity in this country. Lymexylon rfermestoides is about 

 | in. in length, and is found in the trunks of the oak, and some other 

 trees; whilst Lymexylon nasale Fab. (C T antharis navalis 

 Linn., and our fig. 1646.) appears to be exclusively 

 confined to oak timber, which it perforates, and com- 

 pletely destroys. (Gyllcnhal Ins. Suee., i. 317.) So 

 great, indeed, was the injury caused in the royal dock- 

 yards of Sweden by this insect, that the greatest alarm 

 \\ as entertained for the safety of the shipping ; nor did it 164*6 



subside until Linnaeus, at the desire of the king of Sweden, had traced out the 

 cause of the destruction; and had, having detected the lurking culprit under 

 the form of the beetle above mentioned, by directing the timber to be immersed 

 during the time of the metamorphosis of the insect and its season of oviposi- 

 tion, furnished a remedy which effectually secured the wood from its future 

 attacks. (Smith's Introduct. to Bot., pref., p. xv., quoted by Kirby and Spence 

 I/itr., i. p. 237. ; Bechstein and Scharffenburg Forstins., vol. i.) 



Tinea ramella Lin. feeds within the branches of the oak. (Syst. Nat., ii. 

 p. 887.) 



Insects which live under the Bark. There are also many species of insects 

 (chiefly small Coleoptera) which reside beneath the bark of the oak, without 

 boring into the solid wood. Of these, the Scoly tus pygmae\is, already alluded 

 to in p. 1390., as having recently caused the destruction of 50,000 young oaks 

 in the Bois de Vincennes, near Paris, is the most redoubtable. (Annales de la 

 Soc. EntomoL de France, 1836, p. xxx.) Tomicus villosus, I'ps 4-gutttita, 

 Hypulus quercinus, Cerylon pilicorne, Rhyzophagus dispar, Silvanm uniden- 

 tatus, and Bitoma crenata, are also subcortical beetles, the first-named species 

 being one of the typographer beetles. (See Pinus.) 



Insects which feed on the Leaves. It is, however, upon the leaves of the oak 

 that the greatest proportion of its insect population finds its support; and it 

 is chiefly amongst the caterpillars of lepidopterous insects that the greatest 

 number of the leaf-feeders 

 are found. Of these, the 

 Y'ortrix viridiina Lin. (Jig. 

 Mi 17.), a very small, pretty, 

 green species, is by far the 

 DBOtt obnoxious; entirely 

 stripping the oaks of their 

 foliage, BS we have more than 



once observed at Coombe 



Wood, in Surrey. " Even 

 the smaller sorts of cater- 

 pillars become, from their 

 multiplicity, sometimes as 



uVetructirf is those which 



are of < on .iderahle magni- 

 tude. During the summer of |H;>7, we were told that an extraordinary 

 Might had suddenly destroyed the leaves of all the trees in the Oak of 

 Honour Wood, Kent. On going thither, we found the report but little 

 anted; tor, though it was in the leafy month of June, "there was 

 leaf to be seen on the oak frees, which constitute the greater 

 portion of the wood, lint we were rather surprised when we discovered, on 

 examination, that this extt n live destruction had been effected bv one of the 



1647 



