class="hanging">Spinnerets. Organs observed in various parts of the body, producing the waxy, cottony, or mealy matter. They consist of cylindrical internal tubes, sometimes ending on the skin, sometimes protruding outside it in the form of tubes, spines, or conical hairs. In the former case the orifices show them to be in some instances simple, and in others compound tubes.[B] In the Diaspidinæ, besides being scattered over the body, the spinnerets are arranged in groups on the last abdominal segment, and these groups afford excellent characters for specific distinctions. (Plate I, Fig. 4, for types of various spinnerets; Plate III, groups of spinnerets of Diaspidinæ.)

Spiracles. "Breathing organs:" the orifices in the body of the tracheæ or tubes conveying air to the blood. In the Lecanidinæ they are usually four; simple circles, near the edge of the body, and with a few strong spiny hairs near them. In the Coccidinæ they are often numerous. (Plate II, Fig. 4; Plate XX, n.)

Spiracular spines. Spiny hairs, usually three in number, of which one is rather long, close to the spiracles, in the Lecanidinæ.

Stigma, stigmatic spines. Terms sometimes employed for spiracles, &c.

Tarsus. The fourth joint of the feet, between the tibia and the claw. Its consisting of one joint (monomerous) is a distinctive character of the whole family. (Plate I, Fig. 6, ta.; Fig. 7, ta.)

Test. The waxy, glassy, or horny covering produced through the spinnerets and concealing the insect in many Lecanidinæ and some Coccidinæ. In this work it is not applied to the "scale" of Diaspidinæ or to cottony secretions.

Thoracic band. An appearance seen on the thoracic region in the male, looking like a broad transverse ribbon.

Thoracic region, thorax. That part of the female or the male which bears the three pairs of feet, when the feet are present; or, if the feet are absent, the middle portion of the body, segmented or not.

Tibia. The third joint of the feet, next the femur. (Plate I, Fig. 6, ti.; Fig. 7, ti.)

Tracheæ. Tubes ramifying throughout the body, conveying air to the blood. Their orifices are the spiracles. The tracheæ, as in other insects, appear as if constructed of a network of fine spiral wires. (Plate II, Fig. 4 d; Plate xx., n.)

Trochanter. A small articulation, not a distinct joint (something like a knee-cap) of the feet, between the coxa and the femur. (Plate I, Fig. 6, tr.; Fig. 7, tr.)

Trimerous. Three-jointed.

Ventral. On the under-side, the insect being in its proper position.

NEW ZEALAND SCALE-INSECTS

(COCCIDIDÆ).

CHAPTER I.

INTRODUCTORY.

Insects are divided by naturalists into several principal orders, the distinguishing marks of which are generally very well defined—for example, the butterflies and moths belong to the order Lepidoptera, the dragon-flies to the Neuroptera, the common house-flies to the Diptera, and so on. These orders are founded upon the characters and arrangement of the wings. They are subdivided into families, and these again into genera and species. One of the orders is that of the Hemiptera, which is composed of the two following sections:—

Hemiptera-Heteroptera, including the bugs, water-beetles, &c.

Hemiptera-Homoptera, including the crickets, cuckoo-spits, plant-lice (Aphides), leaf-hoppers (Psyllids), scale-insects (Coccids), &c.

The insects treated of in this volume are therefore placed as follows:—

Class—Insecta.
Order—Hemiptera.
Section—Homoptera.
Family—Coccididæ.

The genera and species will be found in their places.

The common English name for this family—"scale-insects"—is not very appropriate. Some few of them have the appearance of small thin scales on leaves or twigs, but many have not. Nor are the German appellations—"gall-insekten" or "schild-lause"—more appropriate. Gardeners have given to some of them the name of "mealy-bug," which, although decidedly neither elegant nor euphonious, very fairly represents the character of that particular portion of the family.

The origin of the name "Coccididæ," or, as abbreviated often in this volume, "Coccids," is found in the old Greek word "[Greek: kokkos]," denoting a rich red dye, which was much admired by the Greeks and Romans, and which was procured from the insect now known as Kermes vermilio (the Coccus ilicis of Linnæus). When the cochineal insect was discovered in Mexico it soon overpowered all the others, producing commercial dyes, and from it has come the title "Coccid," now applied to the whole family. Cochineal itself has of late years been pushed aside to a great extent by the aniline (coal-tar) dyes; yet it is still used for many purposes. This insect lives on the leaves of cactus. Amongst the New Zealand species described in this work will be found one, Dactylopius alpinus, which produces a red dye similar to, though probably not equal to, cochineal. Before the discovery of aniline dyes it might possibly have been worth while to cultivate this insect for its dye; but this would scarcely answer now.

The Coccididæ are, in some parts of the world, very injurious to vegetation. They seem to affect principally the warmer