158 INDIRECT INJURIES CAUSED BY INSECTS. 



imago states, in the bark of Norway fir masts imported to Southampton,) Hy- 

 lurgus piniperda, as well as two large weevils, Pissddes notatus and Pini, 

 which have similar habits, &.c. &c. ; and I will conclude the list with 

 stating as a sample of the whole the ravages committed by one of the 

 tribe, Tomicus typographus , .\n Germany, where it sometimes attacks the 

 inner bark in such vast numbers, 80,000 being sometimes found in a single 

 tree, that it is infinitely more noxious than any of those that bore into the 

 wood ; and such is its vitality, that though the bark be battered and the 

 tree plunged into water or laid upon the ice or snow, it remains alive and 

 unhurt. The leaves of the trees infested by these insects first become 

 yellow ; the trees themselves then die at the top, and soon entirely perish. 

 Their ravages have long been known in Germany under the name of 

 Warm trokniss (decay caused by worms) ; and in the old liturgies of that 

 country the animal itself is formerly mentioned under its vulgar appella- 

 tion, " The Turk." This pest was particularly prevalent, and caused 

 incalculable mischief about the year 1665. In the beginning of the last 

 century it again showed itself in the Hartz forests — it re-appeared in 

 1757, redoubled its injuries in 1769, and arrived at its height in 1783, 

 when the number of trees destroyed by it in the above forests alone was 

 calculated at a million and a half, and the inhabitants were threatened 

 with a total suspension of the working of their mines, and consequent 

 ruin. j\.t this period these Tomici, when arrived at their perfect state, 

 migrated in swarms like bees into Suabia and Franconia. At length, 

 between the years 1784 and 1789, in consequence of a succession of 

 cold and moist seasons, the numbers of this scourge were sensibly dimi- 

 nished. It appeared again, however, in 1790 ; and so late as 1796 there 

 was great reason to fear for the few fir-trees that were left.^ 



When the sap flows from a tree in consequence of the attacks of the 

 above-mentioned insects, or any other cause^, it is attended by various 

 beetles, as Cetonia aurata, several Nitidul<z and Brachyptera, 6cc., which 

 prevent it from healing; and if the bark be anywhere separated from the 

 wood, a numerous army of wood-lice, earwigs, spiders, field-bugs, and 

 similar subcortical insects take their station there, and prevent a re-union. 



assailants are silently at work on the rest, it is evident that the whole avenue is eventually 

 doomed to destruction, and that a century must elapse before it can resume that grandeur 

 which it might have retained for ages had the economy of these insects been understood, 

 and the proper measures for extirpating them taken at the outset. It has been well observed, 

 that in many cases a palace had belter be burnt than the fine old trees that surround and 

 ornament it destroyed, as the former may be rebuilt in a few years, while no cost can 

 replace the latter; and a reflection somewhat similar must have passed through the mind 

 of Napoleen, had he lived to witness the present broken, patched, and miserable aspect of 

 one of the most striking and indispensable features of his triumphal arch, and to see in 

 prospect, that even when the last victims to the destructive attacks of the despised Scolyti — 

 foes which, from his ignorance of entomology, had conquered even him — should have been 

 cut down, and the unsightly gaps attempted to be filled up by planting young trees in their 

 place, neither he nor his successor could ever witness in this the proudest monument of 

 liis reign the mingled splendor and grace which it would have exhibited, if approached, as 

 he meant it to have been, througli a full-grown, entire, and majestic avenue. 



' Wilhelm's Recreations from Nat. Hist., quoted by Latreille, Hist. Nat.xy. 194. 



- While attending to the Srolijti infesting the common elm during the tour in the north 

 of France in 1836, above referred to, I noticed in the liquid matter so often seen constantly 

 oozing from the large ulcers in this tree a dipterous larva in considerable numbers, of which 

 this exudation is evidently the natural food ; and having bred .some of them, they produced 

 very minute gnat-like flics, of the genus Ceratvpogon, probably (but I have not the speci- 

 mens now at hand to compare with his description) C. flavifrons of Guerin {^Ann. Soc. Ent. 

 de France, ii. 165.), which he found in a similar situation. 



