Page:Popular Science Monthly Volume 71.djvu/231

Rh found mixed with, it several worms, not yet altogether changed into pupæ, of a color which from ashen was becoming purple, and which when immersed for a while in water, assumed the form seen in the engraving under the letter C. Hence there came to me the suspicion that under this form appeared the worm of the cochineal before giving itself to rest; for that it certainly belongs to this family, I am persuaded by the purple color which it discharges into the water in which it is immersed, just like the cochineal itself. For when all the eggs of these insects are not hatched in one precise day it at least becomes probable that neither are all these worms in one moment transformed into pupae, or the beetles simultaneously creep forth from these. So, without doubt, when the harvest of pupæ is at hand, several of these worms, which have not yet reached the pupa state, and also several adult beetles, are shaken off at the same time from the tuna. Consequently, we usually find them all mixed, in more or less abundance, with the best cochineal." The worms thus found may be the true larvæ of the ladybeetle, or in other cases, the larvæ of certain two-winged flies of the family Syrphidæ, which also prey upon the cochineal. The presence of the flies is especially indicated by another observation of Friedel's—that he found even a few cup-shaped objects, in which were occasionally seen some small grains of cochineal. Here, he thought, were actually the skins left empty after the exit of the beetles; but on further reflection he abandoned the idea, as they really were not large enough to hold the beetle. The grains found in them were very minute, and were doubtless only cochineal larvæ which had wandered in by accident; and finally, some of these cups still contained, not a beetle, but a single fly. These were, we may now rest assured, the puparia of a predatory Dipterous insect, either a Syrphid or a species of Leucopis.

By the time of Linnaeus, some fifty years later, it was clearly known that the cochineal had nothing to do with the beetles, but belonged to the Hemiptera. Even then, however, it seemed fated to be a source of error and misunderstanding. When Linnaeus was preparing his great "Systema Naturæ," a friend of his, Daniel Rolander, resident in the "West Indies, sent him what he supposed to be unusually fine specimens of the cochineal alive on a piece of cactus. Linnæus naturally used these in making his description of the Coccus casti, and until 1899 nobody seems to have suspected that they were not the real cochineal. However, Rolander sent some at the same time to DeGeer, who figured them, and from the account he gives, and indeed also from that of Linnæus, it is evident that the Coccus cacti L. is no cochineal, but a species of a quite different subfamily, which, curiously, has never been found by any entomologist since it was discovered by Rolander.