4. _The full-grown insect._ Here there is almost unlimited variety of form, colour, and habits. The insects may be naked or covered, active or stationary. In the _Diaspidinæ_ the process just described is repeated: the female slips out of her second skin, but still keeps both it and the first over her, adding more fibrous secretion from the spinnerets; so that, in fact, she lies an inert, legless, slug-like object, under a covering composed partly of the two skins, partly of secretion. (See Plate i., Fig. 3: _a_ is the discarded larval skin, _b_ the discarded skin of the second stage, both being used as part of the shield. In the genus _Aspidiotus_ these skins would be in the centre instead of at one end.) In the _Lecanidinæ_ (except in one single genus) and the _Coccidinæ_ the second skin is discarded altogether; but the insect may either construct a new shield or remain naked, may be either with or without legs, either active or stationary. Once this last stage of her existence entered upon, the female prepares for laying her eggs. In most species the services of a male are needed; in some, as far as can be made out after investigation of many years, no males are found. The female, if naked, either hatches her eggs in her own body or lays them on the plant; if covered, she fills her shield with the eggs. The naked insects often cover the eggs themselves--e.g., _Lecanium hemisphæricum_; or, again, deposit them in an ovisac, a mass of cottony secretion--e.g., _Pulvinaria camellicola_ or _Icerya purchasi_. II. The Male Insect. It has been remarked above that, as the full-grown males of the _Coccididæ_ are destitute of any organs for feeding whatsoever, there is no reason for making systematic attacks on them for economical purposes. Their function is simply to impregnate the females, and their life at this stage must necessarily be very brief. It will suffice in this place to observe that in all cases these males are small, two-winged flies, their size varying from about 1/40 in. to 1/4 in. in length; colour usually yellow or red; wings longer than the body, hyaline (glassy) and often iridescent, and, in repose, lying flat, partly crossing each other. The antennæ are long, slender, and hairy, consisting of nine or ten joints. The legs are also slender and hairy, the tarsus having only one joint, and terminating in a single claw. The insects are generally very active. Types of antenna, foot, wing and haltere, and a diagram of the arrangement of the eyes and ocelli, are given in Plate i., Figs. 7, 12, 13, 14, 15, 17. The males are thus so small and rapid in their movements that it is difficult in most cases to find them in a free state. The usual way to procure them is by hatching them from the pupæ. In their course of life they pass through four stages, as do the females--viz.: 1, the egg; 2, the larva; 3, the pupa; 4, the full-grown insect.