Yes, John, the tiny, dark-colored scales that look like little oyster shells on the skins of oranges are a form of scale bug, and a very troublesome one, too, to the orange grower.
But though most of these insects are troublesome, the family is redeemed by a few members that are of great value to us.
One of these is the scale bug that supplies shellac, and all that comes from it to our markets. These curious bugs give forth a resinous substance that envelops the eggs and glues them to the twigs whose juices the bug sucks out. It is this resinous substance that is collected by breaking off the twigs where the insects are. It is used for varnishes, as you know, and for polishing wood and other substances.
There are other scale bugs that secrete wax, and some of them produce it so abundantly, and of such good quality, that it has become an article of commerce. China wax, which is wax of a very fine quality, is secreted by a Chinese scale bug, and the wax is used for making fine candles, as well as for other purposes.
In Mexico we have the cochineal insect, which is a scale bug that lives on a cactus that grows in Mexico.
Like many others of the scale bugs, the cochineal males have wings and are not so scalelike as their helpless mates.
But they are of no use to us. It is only the female cochineal we use.
She is raised in great numbers in cactus gardens planted on purpose.
Here is the picture of a cactus with cochineal insects upon it.
