2 HO ARBORETUM AND FRUTICETUM. PART III. 



Of the internal Feeders which bore into the solid Wood, the species of the 

 genus 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 the 

 species are coloured similarly to those insects. They especially abound in 

 cold and mountainous regions, where the pines and other coniferous trees 

 abound j and during flight they make a loud humming noise. The best 

 known species, Su'ex gigas iiw??., attacks 'J^bies excelsa (^Rossmdssler, Forstins.) 

 It is very common in Sweden, and in the Alps and Pyrenees. The females 

 are provided with a very strong horny ovipositor, by means of which they 

 deposit their eggs in the crevices of the trees. The larvae, when hatched, bur- 

 row into the wood in various dii'ections : they are fleshy and cylindrical, with 

 a scaly head, six very minute pectoral feet, and a horny point on the upper 

 side of the extremity of the body. (Latr. Hist. Gcner., xiii. p. 149.) " The 

 species of the genus Sirex, probably all of them in the larva state, have no 

 appetite but for ligneous food. Linnseus has observed this with respect to S. 

 spectrum and Camelus ; and Mr. Marsham, on the authority of Sir Joseph 

 Banks, relates (Linn. Trans., x. 403.) that several specimens of S. gigas were 

 seen to come out of the floov of a nursery in a gentleman's house, to the no 

 small alarm and discomfiture of both nurse and children." {Introd.'to Ent., i. 

 p. 231.) In this case, it is evident that the floor of the room must have 

 been recently laid down, the planks containing the sirexes either in the 

 larva or pupa state ; and that they made their appearance on attaining the 

 imago 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 of 

 Sirex 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 larvae of this insect ; some 

 of which still remained in the wood. Of this tree, 20 ft. were so intersected 

 by the burrows, that it was fit for nothing but fire-wood ; and, being placed in 

 an outhouse, the perfect insects came out every morning, five, six, or more 

 each day. The females averaged one in twelve for the first six weeks; but 

 afterwards became more plentiful, and continued to make their appearance 

 until the end of November ; females being only produced during the last two 

 or three weeks. {Trans. Ent. Soc. London, i. p. Ixxxv.) At the same meeting 

 of this Society, it was also stated by the Rev. F.W.Hope, that, in his father's 

 grounds at Netley, in Shropshire, the Sirex generally attacks those trees 

 which have passed their prime ; and that the Weymouth pines are more sub- 

 ject to their attacks than the Scotch pines. These statements will be quite 

 sufiicient to disprove the recently published view of the Count de Saint Far- 

 geau {Hist. Nat. Ili/menopt., tom. i.), that the Siricidae are parasitic upon 

 other 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 

 (C'urculionidae), one of the largest British species of which is thus injurious : 

 it is the Ilylobius abietis of Oerniar (C'urculio abietis of Linnaeus, 6'urculio 

 pini Marsham, Sfc.). This insect varies in length from half to three quarters 

 of 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 in 

 Scotland, and especially in Sweden, it is very abundant and destructive. A 

 memoir upon the habits of this beettle has been i)ublished by Mr. W. S. 

 M'Leay, in the Zoological Journal. A great failure of the young firs and 

 larches on Lord Carlislp's estates in Scotland had taken place, which was at 

 first thought to be occasioned by mice, so completely was the bark destroyed. 

 The wood warden was, however, subsequently convinced that the mischief 

 was produced by insects, of whicii specimens were forwarded to Mr. W. S. 

 M'Leay. The destruction was more rapid when the roots of the Scotch fir 

 were in a state oi decay ; a circiunstance strongly supporting the opinion that 



