SCALE-INSECTS. 11 



%> the y oim g larva ; 3, the second stage of life, or 

 " pupa ; " 4, the adult, or full-grown insect. 



1. The egg. This is, in all cases, of regularly-oval form, 

 the colour varying from' white to yellow or red (see Plate i., 

 Fig. 1). It may be produced in great numbers, and in some 

 cases several times in a year. As a general rule, the female ejects 

 the eggs from her body; but there are some species, notably 

 in the group Lecanidinae, where the eggs are hatched within the 

 body, the insect being thus, in a manner, viviparous. 



2. The young larva (Plate i., Fig. 2) . This is of precisely 

 the same form both for the male and the female or, rather, 

 perhaps it should be said that no definite character has yet been 

 discovered to show which are male and which are female larvse. 

 Neglecting slight variations of form, the larva is very minute 

 seldom more than about ^iii. long, often as small as T J<jin. 

 oval, flattish, possessing a rostrum and accompanying bristles 

 (setae), six legs, and two antennae : and in all species it is fairly 

 active, travelling as soon as hatched over the plant in search of 

 food. 



3. The second stage. Here the first distinction is noticeable 

 between the male and the female in most cases ; but this dis- 

 tinction usually depends not so much upon the form of the 

 insect as upon the character of the covering it makes for itself. 

 Confining ourselves at present to the female, there are differences 

 now noticeable between the groups. In the Diaspidince the 

 insect begins by slipping out of the skin of the larva ; but it 

 does not cast it aside altogether : it makes use of the old skin 

 as part of its covering. Adding to it a small portion of fibrous 

 secretion produced by organs called " spinnerets/' which will 

 be noticed presently it attaches itself to the plant by its rostrum 

 and setae, and lies, inert and stationary, under a little shield 

 composed half of its old skin and half of secretion. As it also,, 

 in entering this stage, loses its legs altogether, it must remain 

 in the position it has chosen for the rest of its life. In the 

 Lecanidinae and in the Cocddinae the skin of the larva is thrown 

 away altogether, and the female in her second stage takes up a 

 new position, in which she may be either naked or covered with 

 a thin coat of secretion, active or stationary, retaining her legs 

 in most cases, or loring them in some instances. In all the 

 groups there is almost always some approach to the form of the 

 full-grown insect noticeable in this second stage. 



