THE VICTORIAN NATURALIST. 141 



GROUPS. 



i. Female insects constructing for themselves shields composed 

 partly of secretions, partly of the pellicles discharged from 

 earlier stages ; abdomen not cleft ; legs lost at full growth. 



DlASPIDIN/E. 



2. Female insects naked, or covered with shields of secretion, 



either waxy, horny, cottony, or felted ; abdomen in all stages 

 cleft; legs either lost or retained at full growth. 



LECANIDINyE. 



3. Female insects naked, or covered with shields of waxy 



secretion ; abdomen of larva ending in prominent processes; 

 abdomen of adult cleft; legs either lost or retained at full 

 growth. Hemicoccidin^e. 



4. Female insects naked, or covered with secretion, either waxy, 



cottony, or felted ; abdomen in all stages ending in pro- 

 minent processes ; legs either lost or retained at full growth. 



Coccidin^;. 

 life history. 

 All of them pass through four stages of existence : — i, the egg; 

 2, the young 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 regular oval form, the 

 colour varying from white to yellow or red. 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 the 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. — This is of precisely the same form 

 both for the male and the female ; or, rather, it should be said 

 that no definite character has yet been discovered to show which 

 are male and which are female larvae. Neglecting slight varia- 

 tions of form, the larva is very minute — seldom more than about 

 one-thirtieth of an inch in length, often as small as one-hundredth 

 of an inch — oval, nattish, possessing a rostrum and accompanying 

 bristles (setae), six legs, and two antennae ; 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. Con- 

 fining ourselves at present to the female, there are differences 

 more noticeable between the groups. In the Diaspidinae 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 apart 

 of its covering. Adding to it a small portion of fibrous secretion 

 — produced by organs called " spinnerets," which will be noticed 



