10 INSECTS NOXIOUS TO AGRICULTURE. 
from Hymenopterous parasites, of which some account will be. 
found in a subsequent chapter (Chap. IV.). 
The effects of the Coccidide are not confined altogether to’ 
damage to plants: there are some species producing materials 
useful to man. For example, Coccus cacti produces cochineal;_ 
Yarteria lacca produces shellac; Ericerus pé-la is used by the 
Chinese for candles: and others might be mentioned. But, so 
far, no New Zealand species appears to be of any commercial 
use. Dactylopius alpinus makes a rather rich red dye in alcohol ; 
Celostoma zealandicum constructs thick, waxy coverings, which 
might possibly be turned to some account; but even these are 
probably not worth much. 
Groups. 
The groups into which the Coccidide are, in this work, 
divided are as follow : 
1. Female insects constructing for them- 
selves shields composed partly of 
secretion, partly of the pellicles dis- 
carded from earlier stages; abdomen 
not cleft; legs lost at full growth. Drasprpinz. 
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. LECANIDINE. 
3. Female insects naked, or covered with 
shields of waxy secretion; abdomen 
of larva ending in promiment pro- 
cesses, abdomen of adult cleft; legs 
either lost or retained at full growth. Hemicoccipin. 
4, Female insects naked, or covered with 
secretion either waxy, cottony, or 
felted ; abdomen in all stages end- 
ing in prominent processes ;_ legs 
either lost or retained at full growth. Coccipin. 
Life-history. 
The life-history of the imsects in the above groups is as 
follows :— 
All of them pass through four stages of existence: 1, the 
