THE INJURIOUS SCALE INSECTS AND MEALY BUGS, &c. 221 
wonderful product which she manufactured during life, and which all 
the world over is of so great importance in commerce. And this is not 
all ; the bodies of the females also furnish an excellent dye, which in 
former times was of much value also. 
The "cochineal insect" (Coccus cacti) is also a true coccid. Before 
the discovery of aniline dyes this species afforded us a most valuable dye 
product, which, although superseded to a very great extent, is still 
largely used for dyeing valuable fabrics such as silk, and it is, I believe, 
used exclusively as a crimson dye for colouring sweetmeats and confec- 
tionery. A species of Kermes, in shape remarkably resembling a large 
crimson holly berry, is also imported for the value of its dye, for which 
purpose it has been used from time immemorial. Ericerus pe-la is a 
coccid of some value to the Chinese. This insect, like many others 
(including British species) secretes a pure white wax, which in China is 
collected and made into candles for special use. In India similar use is 
made of a wax obtained from a species of Ceroplastes [C. cerifems). 
In Australia there is a remarkable family of gall-making coccids, 
which, strange to say, are peculiar to the various species of Eucalypti of 
that country. All galls are remarkable, but none could be more so than 
these, and the insects inhabiting them are among the largest of known 
coccids, some of them measuring over an inch in length. The sexes 
usually live apart, inhabiting separate leaves ; but in a few instances the 
female gall often supports a number of males. The female galls are 
considerably larger than those of the males, and act as a sort of prison- 
house, from which they never escape. The male galls also remain intact 
until the insects are ready to escape, when a portion of the gall falls 
away, liberating the insects. Fertihsation is accomplished by the male 
inserting its long genetalia into a small opening in the gall which leads 
to the hidden female. 
A very large proportion of the coccids possess the power of covering 
or protecting their bodies with a natural secretion, which assumes various 
forms in the different sub -families. We have already seen how this is 
accomplished in the "lac insect," and hoAV the Australian Brachycelinae 
protect theirs by making galls on their food-plants. When we come to 
consider the British species we shall find that the secreted coverings 
which many of the insects make form a very important item in their 
economy, and it may be well for practical purposes to consider them 
under different headings, according to the nature or absence of secretionary 
matter. Such a division as I propose is by no means scientific in its 
arrangement, but it may materially help the horticulturist in obtaining a 
clearer idea as to what he has to contend with in making applications of 
insecticides to these pests. 
(1) Species protecting their bodies with a scale or shield com- 
pletely covering the insect beneath. This may be hard and horny, 
tough and leathery, or thin and transparent. The adult females are 
without legs and antennae, and include Mytilasjns 'pomorum, Diaspis 
roste, &c. 
(2) Species in which the females are naked in all stages. The pupae 
of the males are covered with a glassy scale, but these are in most cases 
^exceedingly rare, and do not materially concern us.' The Peach Scale 
D 2 
