SCALE-INSECTS. 7 
chance that the honeydew spray so falling will be disturbed. It 
consequently rapidly accumulates and forms a coating on the 
leaf where it rests. From this result two things, or, rather, the 
same injurious effect on the plant is produced in two ways. First, 
the honeydew itself, being, as stated, of a glutinous nature, tends 
to stop up and choke the stomata (or, in plain English, the 
breathing-orifices of the leaves) and so retard the growth of the 
tree. Secondly, the honeydew, being of a saccharine nature, is 
especially attractive to fungoid growths, and these fungi, rapidly 
increasing, tend still more to choke the leaves and hamper the 
proper functions of the tree. 
The second of these is the most important, for, apparently, 
the honeydew is scarcely deposited before it becomes the recep- 
tacle for fungus-spores, and these grow with great rapidity. As 
a general rule, in New Zealand, these fungi appear to be mostly 
of the same family—the Physomycetes, and they are of a black 
or very dark brown colour. From the fact above stated, that 
the honeydew falls from the insects upon leaves beneath them, 
the lower leaves of a plant are more covered with it than the 
upper ones: these black fungi consequently discolour chiefly the 
lower leaves and branches; often the uppermost branches are 
nearly free from them. But the effect produced on the tree is 
not only unsightly, from the sooty blackness, but also injurious, 
from the choking-up of the stomata both by the honeydew and 
the fungus. As for ornamental plants, whether under glass or 
in the open air, the black coating is quite sufficient to spoil 
them. 
These fungi are of various species, and specimens are given 
here in Plate xxil.: on the leaves they form usually a hard, thin, 
black coat; while on the twigs and stem they are of a looser 
texture, forming masses of minute erect threads. They are not 
confined to New Zealand, and most writers on Coccididze in 
Europe and elsewhere mention them, though only casually. 
They are, in fact, apparently, only the usual growths appearing 
on any decomposing substance, such as the honeydew is. 
Gardeners and tree-growers ought to clearly understand that 
the appearance on their plants of this black sooty covering is 
almost always an indication of the presence of some Homo- 
pterous insects. In New Zealand, on account of the greater 
prevalence of Coccidide, the insects will most probably be 
Coccids ; but by no means necessarily so, for many Aphididz, 
2 
