THE INJURIOUS SCALE INSECTS AND MEALY BUGS, &c. 223 
almost invariably left behind upon the plant. This character is common 
to many coccids, but it is so marked in this species that it may serve to 
identify the insect. 
The female, like so many others of this family, is bright yellow, and 
when the ova mature they show as darker spots through the transparent 
integument. 
Although this species has been under careful observation for many 
years, the male sex has never been discovered. The absence of males 
among coccids is a quite common occurrence, and there seems no 
difficulty on the part of the females to reproduce their species without 
the intervention of the male. 
This insect only occurs under glass in this country, but lives in 
M^r(- 
Fig. 95. — Oyster-shell Bark Louse or Scale 
{Aspidiotus ostrea'forviis) on Plum branch (nat. size). The small branch to the 
right is from a healthy tree, and is free from scale. 
the open air in the south of Europe. I have also received it from 
North Africa, and it is met with in many other parts of the world. It 
increases most rapidly in a " stove," being less productive in cooler 
houses. 
It is especially attached to the Camellia and Fig, but occurs on a 
number of other plants, including Asparagus plumosus, Myrtle, 
Euonymus, Begonia, &c. 
Oyster-shell Bark Louse or Scale 
(Aspidiotus ostrecBformis , Curtis=^. betuke, Barensprung). (Fig. 95.) 
This insect takes its name from the scale covering, assuming some- 
what the form of a miniature oyster shell, which character is most 
