THE INJUKIOUS SCALE INSECTS AND MEALY BUGS, &c. 'ill) 
THE INJURIOUS SCALE INSECTS AND MEALY BUGS OF 
THE BRITISH ISLES. 
By Mr. R. Newstead, F.E.S., 
Curator of the Grosvenor Museum, Chester. 
[Read October 10, 1899.] 
^YITH Photogeaphic Illustrations by the Weitee. 
The scale insects " and " mealy bugs " are generally termed *' coccids. * 
They belong to the extensive order Hemiptem, which contains the two 
great sub-orders Heteroptera and Homoptera. The former contains, 
among other common insects, the " plant bugs," " bed bugs," water boat- 
men, and water scorpions, kc. ; while the Homoptera includes the 
"plant lice," " frog hoppers " and " cuckoo spits," kc, and the destruc- 
tive coccids {Coccidce), which it is my pleasure to deal with in this paper. 
The minute structural details will be briefly dealt with, and only such 
facts as may be considered essential or of economic importance will be 
given. The salient characteristics by which the CoccidcB may be known 
from all other insects are — 
(1) The females are destitute of wings ; legs and antennae either 
present or absent ; mouth, formed for sucking up the juices of the plant, 
is present in all but one remarkable exotic genus. 
(2) Males possess one pair of wings ; but not a few are apterous, 
or wingless. The most remarkable character is, they are absolutely 
without a mouth, its position being occupied by one or two pairs of eyes. 
(3) Larva, a minute active six-legged insect, both sexes possessing 
mouths as in the female. 
With the exception of two genera — Exeretopus, Newstead, and 
Olifiella, Cockerell, both males and females are also characterised by pos- 
sessing a single -jointed foot (tarsus), furnished with a single claw, and 
usually two to four knobbed hairs. In the abnormal genera referred to 
above the front tarsi are double-jointed, while the other tarsi are normal. 
As coccids usually occur in large colonies, they may be generally con- 
sidered as injurious to plant life. Of course there are many novelties 
among them, which from their rarity can scarcely come under this head- 
ing ; but the horticulturist may safely regard all of them with suspicion, 
and apparently harmless species should be given no quarter. 
Three species are of interest as furnishing us with commercial pro- 
ducts. " The lac insect " (Tachardia lacca) is of the first importance, 
as it furnishes us with the invaluable product known as " lac," which 
forms a basis for varnish, French polish, and many other equally 
important materials. It is usually imported into this country upon the 
twigs or small branches of the trees upon which the insects have secreted 
it, and is known commercially as " stick lac," which, after treatment, is 
made into "cake lac," and finally into "shell lac," a material known to- 
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