Bugs, Cicadas, Aphids, and Scale-insects 187 
very few years had so naturally increased and spread that the ruthless scale 
was definitely checked in its destruction, and from that time to this has 
been able to do only occasionally and in limited localities any injury at all. 
Fig. 254. —The fluted scale, Icerya purchasi, attacked by the Australian ladybird-beetle, 
Vedalia cardinalis. In lower left-hand corner a Vedalia which has just issued from 
its pupal case. (From life; upper figure slightly enlarged; lower figure much 
enlarged.) 
Of the second group, the best-known scales are the various species of the 
genus Lecanium (Fig. 256). Of these, the olive or oleander or black scale, 
L. olecB, as it is variously called, is the most widely distributed and abundant 
and hence economically important. It is a long-known species, having 
been described in Europe in 1743, and it was brought to this country in 
early days. The adult females are blackish, almost hemispherical, rough¬ 
skinned creatures, with no external indication of head or other body divi¬ 
sions, feet, antennae, etc., all these parts being visible only from the ventral 
aspect, which normally is closely applied to the leaf or twig. On the back 
may be distinguished three ridges forming an H. The young are flatter 
and light brown, but can be recognized by their even more distinct H-mark. 
This scale is found all over the United States and has a wide range of food- 
plants, garden-bushes of all kinds, as well as deciduous and citrus fruits 
being attacked. In California it is one of the worst insect-pests of the olive- 
tree and also one of the worst of the orange enemies. It has certain natural 
enemies in the persons of various ladybird-beetle species, and a few special 
ladybird-beetles have been imported from Australia and elsewhere in the 
hope of repeating the signal Vedalia success. Only a fair measure of suc¬ 
cess has been achieved. An indirect but serious injury caused to plants 
by the black scale is due to the germination in the honey-dew secreted by 
it of the spores of a fungus, Capnodium sp., which^spreads its felted mycelia 
