THE COCCID.'E. 
3«3 
curious white cottony stuff which encircles them and protects them 
from the air. When we crush this white mass the Aphis within it 
bursts, and a red stain is produced like blood. Some others live 
in groups, which are enclosed in the galls which they produce by 
irritating the structures of certain plants. 
The family of the Coccidce are very closely allied to the 
Aphidce, and are frequently called scale insects or mealy bugs. 
They are very interesting, and may be easily distinguished from 
the plant lice. The development of the Coccidce does not progress 
so regularly as it does in the Aphides, and it stops short, and 
even retrogrades in most remarkable manners. They do a great 
deal of harm to vegetation ; but some, such as the cochineal 
insects, are most useful to man, on account of their furnishing 
magnificent colouring matters and inducing commerce. 
In the engraving on page 381 the rounded scale-like insects on 
the cactus are females. The female Cocci possess a certain amount 
of activity when they are born, and they search out leaves and twigs 
or stems upon which they intend to feed. Having made up their 
minds they stick their sucker into the tissue of the plant, and can 
never take it out again. They are found firmly attached to it, and 
it will be noticed that they gradually lose all trace of the articula- 
lations of the body, that they become motionless and apparently 
senseless, so that they resemble vegetable excrescences. They are 
always sucking, and even their courtship is spent whilst they are 
imbibing the juices of the plant beneath them. They lay a large 
quantity of eggs, and produce a greater or less abundance of a 
cottony matter. The egg laying goes on without any movement 
on the part of the mother, and when she dies her body dries up and 
often forms a shelter for the newly born creatures. The larvae, as 
soon as they are born, spread over the branches and leaves, and 
remain there during the warm weather. They are usually very 
small, but they increase to such an extent that the death of the 
plant becomes almost certain. It appears that they are repro- 
duced somewhat like the Aphidce , but only the males have wings. 
The engraving on page 382 represents the males of the co- 
chineal insect highly magnified. 
