Saw-fly. T. moris, Plum Saw-fly, attacks the green-gage, and other plums, when about the size of peas. It pierces them, causing their fall, to deposit its eggs in their pulp. M. Kollar gives these correct particulars of this insect: -

"At a distance it resembles a small house-fly; but it has four wings, whereas the house-fly has only two. The head and body are completely black, and the feet of a reddish yellow.

"It lays its eggs in the notched part of the calyx of the flowers, cuts in obliquely with its saws, without completely piercing it through, and introduces the egg into the deepest part, so that, when it flies away, nothing is seen on the exterior but two very small brown spots.

"The egg is very small, greenish-white, and transparent. It is hatched in the course of a few days, and produces a delicate whitish larva, with a dark-brown head, six pairs of middle feet, three pairs of fore feet, and one pair of anal feet".

T. hoemorrhoidalis, Pear Saw-fly, resembles the former, but is rather larger, and has more yellow about it. The same authority last quoted says that it "appears usually late in May, some of them only in June, if the warm spring weather sets in late. The female lays from forty to sixty eggs, and almost always on the under side of the leaf. The caterpillar, which is hatched in a few days, at first is of a whitish yellow, but becomes darker every day. As soon as it is exposed to the light, it spins a web over itself, the threads of which proceed from its mouth. The caterpillar never appears out of this web; and when it has partly eaten a leaf, it spins itself a web on another, and always in company with the other caterpillars. It has a black head, and, immediately under the throat, two black dots: the other parts of the body are ochre-colored and transparent, without hairs." - Kollar.

T. difformis, Antler Rose Saw-fly. Its caterpillar feeds on the leaves of rose-trees; and they are thus described by Mr. Curtis: -

"They are nearly cylindrical, tapering a little to the tail. They are bright green, and covered with short upright hairs, with a darker line down the back, and one of a deeper tint down each side. Having arrived at their full growth, they spin a web either between the contiguous leaves, or in a fold, by drawing the sides of a leaf slightly together; but sometimes it is attached to the stem only at a fork of the branches. In this web they form a yellowish-white cocoon, somewhat oval. In these cocoons the green larvae rest a short time, losing, it is said, their fourteen false legs, and eventually changing to a pupa. The flies are hatched in twelve or thirteen days. The perfect insect is found from the end of May to the middle of August.

"It would not, perhaps, be an easy matter to get rid of these troublesome caterpillars, except by hand-picking and shaking the branches over a cloth; for, as they keep on the under surface of the leaves, no application except fumigating with sulphur would fairly reach them. It is possible that sprinkling hellebore powder over the leaves would annoy them." - Gard. Chron.

T.populi, Peach, or Poplar Saw-fly, also resembles the first-named, and M. Kollar says that, -

"As soon as the first leaves of the stone-fruits are unfolded in spring, this saw-fly visits them, and attacks the peach, apricot, and plum trees. They choose days that are particularly still and warm, and lay their eggs on a leaf in rows, one after another, from thirty to forty in number, not all at once, but often disburden themselves of their eggs at different times. They are longish, cylindrical, and of a light yellow color.

"If the weather is favorable the eggs are hatched in a few days, and a white-greenish grub is produced from them. They no sooner begin to move than they surround themselves with a web; thus surrounded they roam from one leaf to another, from which they select the best parts for their food; therefore a leaf is never found entirely consumed.

"As soon as they have attained their full growth they retire into the ground, form themselves a chamber, make themselves a dark-brown roomy case, the material for which they produce from themselves, and remain in the earth till spring, when they again appear as saw-flies to propagate their species." - Kollar.

T. grossularioe and T. ribesii are very destructive of gooseberries. Mr. Curtis says that, -

"The larvae, of which there are two generations in the course of the year, live in societies consisting of from 50 to nearly 1000. One family, so to speak, frequently occupy one bush, and destroy all the leaves, thus preventing the fruit from arriving at maturity.

" The larvae are of a grayish colour, covered with small black warts arranged in rows, and have twenty feet. Their transformation also takes place in society, one fixing the end of its cocoon to the end of the next, and so on. Many remedies have been suggested, but none have been attended with perfect success. Perhaps the surest way of all to diminish the numbers is to hand-pick the larva;, and collect the cocoons wherever they appear, and destroy them, thus killing many hundreds in embryo."-Gard. Chron.

T. -pini, T. erythrocephala, and T. ru-fus, infest the pine and fir species.

T. cerasi produces a slimy catepillar, commonly called a slug-worm, very injurious to the leaf of the cherry, plum, and pear. Mr. Curtis observes of "these very singular and inactive caterpillars," that they "are more like little black slugs, or tadpoles, than the larvae of a saw-fly, being entirely covered with a slimy matter which gives them a moist and shining appearance; and when at rest, upon the foliage, they might easily be mistaken for the droppings of sparrows or swallows. Upon closer examination they will be found to exhibit the typical characters of the family to which they belong, having six pectoral and fourteen abdominal feet, but no anal ones. They are of a deep bottle-green color; the thorax is dilated, being very much thicker than the rest of the body, and concealing the head, or nearly so.

"After four or five weeks, when they have arrived at their full growth, they cast off their bottle-green jackets, and then appear in a suit of buff, being entirely changed in their appearance ; they no longer shine, neither are they smooth, but covered with small transverse wrinkles; and, a short time after, they leave the leaves for the purpose of entering the earth, where they spin an oval brown cocoon composed of silk, with grains of the soil adhering to the outside.

"Towards the end of July, after having lain dormant nearly ten months, the flies emerge from their tombs. The female is of a shining black, with a violet tint; the head and thorax are pubescent; the horns are short, pointed, and composed of nine joints; the ovipositor is nearly concealed: the wings are often more or less stained with black.

"The eggs are deposited on the upper side of the leaves, probably under the skin. They are oval, and of a clear yellow colour: the young larvae are hatched from them in a few days. Dusting the infested trees with quicklime is certain death to the larvae, especially in their earlier stages; but it ought to be repeated once or twice, as they change their skins, and can thus, like slugs, get rid of the noxious matter with their slough, for the first time, but not so at the second dusting. On a small scale, the powdered and unslaked lime might be scattered over the leaves with a tin box, having a number of holes in the lid like a dredging-box; and on a larger scale a fine sieve might be used by a man on a ladder or steps. Decoction of tobacco water, about a quarter of a pound of tobacco to two gallons of water, thrown over the trees with a garden-engine, will destroy them.

"Some persons have employed lime-water with complete success; about a peck of lime to thirty gallons of water; and if two pounds of soft soap be added, it will improve the mixture.

"The best periods for applying these liquids, are before seven in the morning and after five in the evening. The syringing should be repeated until the trees are free from the slug worm; they may afterwards be washed clean with pure water; and if the lime water be used in the evening the cleansing may be deferred until the following morning." - Gard. Chron.