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ARBORETUM AND FRUTICETUM.

PART III.

Of the internal Feeders which bore into the solid Wood , the species of thegenus Sirex of Linnaeus (Urocerus Geoffr.), belonging to the order Hy-menoptera, are amongst the largest. In the winged state, they are com-paratively innoxious. They are often as large as hornets; and some of thespecies are coloured similarly to those insects. They especially abound incold and mountainous regions, where the pines and other coniferous treesabound; and during flight they make a loud humming noise. The bestknown species, Sirex gigas Linn., attacks’A'bies excelsa ( Rossmassler , Fvrstins.)It is very common in Sweden, and in the Alps and Pyrenees . The femalesare provided with a very strong horny ovipositor, by means of which theydeposit their eggs in the crevices of the trees. The larva:, when hatched, bur-row into the wood in various directions : they are fleshy and cylindrical, witha scaly head, six very minute pectoral feet, and a horny point on the upperside of the extremity of the body. ( Latr. Hist. Gener., xiii. p. 149.) “ Thespecies of the genus Sirex, probably all of them in the larva state, have noappetite but for ligneous food. Linnaeus has observed this with respect to S.spectrum and Cameius; and Mr. Marsham, on the authority of Sir JosephBanks , relates (Linn. Trans., x. 403.) that several specimens of S. gigas wereseen to come out of the floo'r of a nursery in a gentleman’s house, to the nosmall alarm and discomfiture of both nurse and children.” ( Introd.'to Ent.,\.p. 231.) In this case, it is evident that the floor of the room must havebeen recently laid down, the planks containing the sirexes either in thelarva or pupa state; and that they made their appearance on attaining theimago form. Linnaeus (Syst. Nat., ii. p. 929.) says of Sirex spectrum,“ Habitat in lignis putridis antiquis Pini et Abietis.” Wm. Raddon, Esq.,has lately forwarded to the Entomological Society of London specimens ofSirex juvencus, another large species, of a fine blue colour in the female;accompanied by specimens of the wood of a fir tree from Bewdley Forest,Worcestershire , perforated and destroyed by the larva: of this insect; someof which still remained in the wood. Of this tree, 20 ft. were so intersectedby the burrows, that it was fit for nothing but fire-wood; and, being placed inan outhouse, the perfect insects came out every morning, five, six, or moreeach day. The females averaged one in twelve for the first six weeks; butafterwards became more plentiful, and continued to make their appearanceuntil the end of November; females being only produced during the last twoor three weeks. (Trans. Ent. Soc. London, i. p. lxxxv.) At the same meetingof this Society, it was also stated by the Rev. F. W.Hope, that, in his father’sgrounds at Netley, in Shropshire , the Sirex generally attacks those treeswhich have passed their prime; and that the Weymouth pines are more sub-ject to their attacks than the Scotch pines. These statements will be quitesufficient to disprove the recently published view of the Count de Saint Far-geau (Hist. Nat. Hymenopt., tom. i.), that the Siricidae are parasitic uponother insects, like the /chneumonidae. It is, however, amongst the cole-opterous insects that the greatest numbers of pine-boring species are found;and of these a considerable portion belong to the family of the weevils(Curculionidae), one of the largest British species of which is thus injurious;it is the Hylobius abietis of Germar (Curculio abietis of Linnmus, 6’urculiopini Marsham, #c.). This insect varies in length from half to three quartersof an inch. It is of a pitchy black colour, varied with yellowish pile. For-tunately, however, in this country it is but of rare occurence; although inScotland, and especially in Sweden , it is very abundant and destructive. Amemoir upon the habits of this beettle has been published by Mr. W. S.M‘Leay, in the Zoological Journal. A great failure of the young firs andlarches on Lord Carlisle’s estates in Scotland had taken place, which was atfirst thought to be occasioned by mice, so completely was the bark destroyed.The wood warden was, however, subsequently convinced that the misctuetwas produced by insects, of which specimens were forwarded to Mr. W. *■M‘Leay. The destruction was more rapid when the roots of the Scotch hrwere in a state of decay; a circumstance strongly supporting the opinion that