BORING INSECTS AND THEIR PARASITES.

Nelson Evening Mail, Volume XXV, Issue 208, 2 September 1891, Page 2

BORING INSECTS AND THEIR PARASITES.

There are a large number of boring insects besides the '■ long horned " beetles, which do so much mischief amoug our trees by citing the pith, especially in suoh trees as the citrus tribe, the mulberry, gooseberry, and other soft pibhed variebies. Some of bhe Hymenopbenu have wonderful powers of cutting into hard substances iv the perfect state by means of their auger-like ovipositors, and in the larva, by their mandibles, so much so thafc were the relations of some of fcheir acts not placed beyond all power of doubt ib would nofc be easy to credit them, bufc we have all seen the very hardest of woods, even wheu rendered by seasoning so tough and hard as fco be difficult to out with our sharpest tools, burrowed all through by the jaws of soft pulpy grubs. A thorough examination wifch a microsoope will easily explain the cause, which lies in the excessive sharpnes3 of fche mandibles. If you take fche finest pointed needle and put ifc into a powerful microscope the point will seem like the blunt rounded end of a crow bar, and if you examine the edge of fche sharpest razor ifc will look like a jagged saw. Man has neither the skill nor the material to construct such cutting implements as the auger of a sirex or the mandibles of its larva. Examine the edge of them in the same microscope aud you will sSe a olear cub smooth defined line to represent fche fine edge, or a sharp point running out to nothing fc. represent the end. The material being harder fchan any substance we have without its brittleuess, with such perfeot tools as these, insects can oub 'through, or bore into, any substanoe short of glass, and perform work to which the mere grindings of a codlin moth through corks of b.tfcles, &o, are but child's play. In 1857 during the Russian war the French troops were supplied with cartridges from Turin which had been packed in boxes of larch wood, iv which several larvae of the serix gigas and fche serix ju venous had been living, aud these getting in amongst the cartridges eat their way, not only through paper and powder, but through the leaden bullets, probably to effect their escape, because it has been proved by burning and analysing the bodies of suoh insects, that fchey do not consume suoh materials as they do wood for food, but merely out through whatever hard substance comes iv the way of their burrows. There can be no doubt ac to the facts, because a greab many cartridges were destroyed in this way, and several separate lots were sent as curiosities t i the museum of the Societo Zoologique ab Paris, and others to the Academic des Soienoes, where these now remain. There are ofcher insects besides these Hymenoptera which possess equal and even superior powers of outting through hard substances. The larvaj of some species of Lepidoptera) (or butterflies and moths) live in the wood of trees, whioh fchey cut burrows in, the goat moth (Cossuligniperda) being a familiar example. The cutting powers of the wbite ant are too well known to need any comment here, but there are larvte amongst the G-leaptera, or beetles, whose powers exceed any of these, and aro nofc so generally understood. Several species of Callidium larva) have been known to cut long galleries in the lead roofing of churches, and thereby to do muoh damage. Especially was this the case at the oathedtal at La Rochelle. Experiments with these larvm had been tried, and in one case a callidium sanguineum ate its way through a leaden box. Bub the most remarkable case is one whioh fortunately is oapable' of aotual proof, or no one oould bs expeoted to believe it. It ooourred io "lUZ, and the Incident in related hy a French naturalist, in whose own words Iwill give the story. "M. De Boys has presented to tbe Sooiete d' Agriculture, of Limoges, some stereotyped plates, composed, aB is well known, of a very hard alloy, formed of antimony and lead, whioh had been pieroed and riddled with holes by two specimens of a Bostriohnus*. The holes were a seventh of an inch in diameter, by two inohes deep. . , , 4. the printing/ served for a work called '« bes jWlea . Miliiaires, de la France, " one tpay say that the brave soldiers received from an. inseot -x more wounds than their enemies had ever . givea them. " Next week we propoo,e;tb ■«iya" some aooount of the parasites of eo^pf these insects, whioh might be of prabtiQalTosfifi imported here, -*.;.,;.;.•. ._ . ENXoaroj-oaisT to the Nelson F Qt,&A Xx. WW? 9 . WW ; Xylopbagi tm^jXzAX :V;