The half-inch glass, however, discloses a marvellous example of mechanical excellence. The head of the borer is then seen to be armed with long, sharp teeth, slightly curved inwards, and acting just as does the carpenter’s ordinaiy centre-hit. So much for the head of the borer : we will now turn to the shaft. It appears that, in order to make a clean-cut hole for the reception of the egg, the shaft of the borer has to finish the task which the head begins. Accordingly, it is armed on each of its sides with a series of hard, sharp-edged ridges, running diagonally across it, and acting exactly as do the sharp ridges of a coffee-mill. A more effective implement could not have been invented, and the various boring instruments of modern days, however novel they may appear to be, are in reality formed on exactly the same principle as the borer of the Sirex, though perhaps they may not carry out their object with such perfection.

This is a wood-boring insect, the female drilling a hole in the solid wood, usually that of the fir, and depositing her eggs in

it. It is thought by many natm-alists that the Sirex never

attacks growing trees, hut restricts itself to those which are

either dead or dying. The late Mr. Waterton was of this opinion. Shortly before his lamented death he showed me two fir-trees which he had ‘ girdled’ in order to kill them, for the purpose of seeing whether or not the Sirex would attack them.

Unfortunately, the accident from which he died put a stop to the experiment.

It is, at all events, certain that the Sirex does exist in dead timber, and nothing is more common than to see a newly erected summer-house absolutely infested by the Sirex, which, although harmless enough, looks so like a hornet that scarcely any persons who are not practical entomologists can believe that an insect so formidable in appearance, and armed with so huge a sting, can be anything but dangerous.

In Curtis’ ‘British Entomology’ it is mentioned that the Sirex has made its appearance in York Minster, a number of the males having been captured as they were flying about the tower ; and Mr. Curtis took occasion to prognosticate danger to the tower, not only from the weakening of the timber, but from its increased liability to combustion, owing to the numerous tunnels with which it is perforated.

I have quite a collection of these insects, sent to me by persons who have found them in newly-panelled rooms, in summer-houses, and similar localities, and who have been quite alarmed at their presence. These, however, mostly belong to another species, Sirex gigas, the female of which is yellow and black, like the male, and which therefore looks much more like a hornet than its relative, Sirex juvencus. It is really a splendid insect. One that I have taken at random from a box measures an inch and a half from the head to the end of the tail, the spread of wing is two inches and three quaibers, and the boring apparatus, which is as large as a ‘ No. 5 ’ needle, is rather more than an inch in length, so that if people mistake It for a poison-bearing sting, insect. they are likely to be afraid of the

The colouring of this insect is peculiarly bold. The head is thickly punctured, and deep black, except a patch of bright yellow behind the eyes. The thorax is also black, punctured and covered with a coating of fine black down. The abdomen

is bright ochreous yellow, with the exception of a hroad satin-like belt round the middle, the colour being black, glossed with violet. The boring instrument is brown, with a slight tint of- red in it. The femora, or thighs of the legs, are black, and the rest yellow, and the antennae are yellow. Even the wings have a decided yellow tinge about them.

The reader may remember that most wood-boring insects are exceedingly variable in size. The Sirex is no exception to the rule, for, while some specimens are almost gigantic in dimensions, others are the merest dwarfs by their side.

The larva bears some resemblance in general form to that of the Musk Beetle, described on page 195. The mandibles are and furnished with saw-like teeth at the end, their very strong, action being as remarkable as it is powerful. They remain in state for a considerable time ; but the duration of the the larval existence depends much on circumstances, those which pupal change to the pupal condition in the summer only waiting a or so, while those which change at the end of autumn month have to wait for nearly a year.

As a rule, none of the species of Sirex are very common in They are, however, tolerably plentiful in the this country. of my house, because there is a small fir-wood neighbourhood a hundred yards of it, and that wood has been fenced within from the misshapen firs. That they may off by a paling made common may be seen from an account published be thus locally in the first volume of the ‘Transactions of the Entomological A part of a fir-tree, some twenty feet long, was placed Society.’ and for several months the Sirex juvencus issued in an outhouse, at the rate of five or six per diem. At first they were nearly appeared, and during the last two all males, then a few females females alone made their weeks, i.e. the end of November, wood in question was sent to the appearance. The piece of by Mr. Eaddon, from Bewdley Forest, Worcestershire.

Society now comes before us,

An enormous group of Hymenoptera This name is formed entitled Entomophaga.

appropriately ‘ insect-eating.’ It is given

from two G-reek words, signifying in the larval state, the greater number

to them because, other insects; usually, but not

of them are parasites within still larvae. In them the abdomen

always, attacking them while

is attached to the thorax by a very small portion of its diameter, and is often lengthened into a more or less slender footstalk. The females are furnished with an ovipositor composed of several valves, and similar in most respects to that of the Sirex. Mr. W estwood arranges them in two groups ; the one, which he calls Spiculifera, having ‘ two delicate spicula, working in a horny semi-canal, which is defended at rest by two often partially exserted valves,’ The second division includes those in which the abdomen is terminated by a telescopic retractile tube.

The first family is the Gynipidce, popularly known as Grallflies, in which the ovipositor is internal and more or less spiral, and the antennae are straight and have from thirteen to fifteen joints. By means of the ovipositor, the female insect punctures various portions of plants, the ribs and nervures of leaves, young twigs and roots, being the favourite objects, and by the same instrument she introduces an egg into the wound, together with a drop of some irritant Hquid. The effect of this liquid is very curious. It mixes in some way with the sap of the tree, which causes a swelling to take place, in the middle of which the egg is hatched into a larva, and finds at once its board and lodging combined. As is the case with the Sawflies, the egg of the Gall-fly enlarges after it is deposited, until it IS three or four times as large as when it was first deposited.

he varieties ©f galls, in shape, colour, and size, are almost beyond calculation ; for, despite the enormous number of Gall-flies that are already known, new specimens are still being discovered, and every species makes its own gall. How the instilled liquid acts no one kno ws, and there are few more curious problems in natme than that which the growth of the gall involves. Were each kind of tree, for example, to produce one kind of gall H would be easy enough to understand that the irritating bquid introduced by the insect would produce a certain sorLf abnormal swelling. But when we And that a variety of Gall-flies attack one tree, such as the oak, and that each produces an entirely different gall, the problem is a very perpLing In many cases, such as the LT well-known currant-gall, thf nuton Plate IX. Fig. 6, each gall has but one inhabitant. But in

‘ oak-apple ’ gall and the ‘ bedeothers, of which the common examples, a number of cells are guar ’ of the rose are familiar gall, and each insect inhabits its own enclosed in a common cell.

examine in detail a few of the most prominent We will now The insect on Plate IX., to which referinsects of this group. belongs to the typical genus of the

ence has just been made, it is called Cymps Kollan, in family. By some entomologists and by some it is enhonour of the well-known entomologist, of the hard and almost

titled Cynips lignicola, in consequence gall. In this genus the abdomen is woody structure of the and there is a small, but boldly marked rather egg-shaped, The antennae of the male have triangular submarginal cell. The colour of t is fifteen, and the female fourteen joints. species is dull plain brown. in which insects can spread themselves

The rapid manner are favourable is well exover a district when the conditions a tew years ago it emplified by this aall-fly. Comparatively London. But Mr. h. Sm

unknown in the vicinity of was on which were a number o from Devonshire a branch brought hedge. Next year the oaks and fastened it in an oak the galls, the insect has so rapidly ma e bore these galls in numbers, and known than those of any its way that its galls are now better that they are even strung snecies. They are so plentiful other baskets for holing ferns. on wires, and made into ornamental hedge which is thickly sodded I have in my garden an oak when the galls. Even in summer-time, with the I'oundfhard are easily seen ; but in the leaves are on the trees, these galls the sight, they are the most winter, when no foliage obstructs In this part of the country objects in the hedge. rons;icuous underwood, and abundance of oak i e West Kent, there is great with other oak-lovi „ this spemes, in common in consequence ample subsistence. finds and when the numbers of these Gall-dies

TtW had grL the galls, I was sadly disappointed a first batch escaped from brown colour, -d altogether com*^^ fte dull, sombr'e of the Cyn p , the Still, owing to the sise look of the insect. can be easily made out with structure of the ovipositor and a fair stock o p aid of a tolerable microscope

Sometimes two, or even more, of the galls will be made so close together that they coalesce to a greater or smaller degree. I possess one rather remarkable instance of this fusion. Contrary to the general practice, the instinct of the enclosed insect misled it. After the pupa has changed into the perfect state, the Cynips gnaws its way through the substance of the gall, and so gains the outer air. The distance to be traversed is about half an inch, and the insect has quite enough strength to accomplish the task. But, in the instance of which I speak, one of the Grail-flies had mistaken its way, and, instead of directing itself to the point which would lead it most directly into the open air, unfortunately took exactly the opposite direction, and hit upon the very spot where the galls were joined after the fashion of the Siamese twins. Consequently, instead of having to gnaw its way through a wall barely half an inch in thickness, it had to traverse an inch and a half before it could reach the air. Very naturally, its strength was exhausted before it could perform such a task, and I found it lying dead on the spot where the galls were joined.

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