Page:Popular Science Monthly Volume 79.djvu/436

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caught, and that when they had a good store of these, they laid them in hags at the feet of their monarch." A more scholarly, not to say more spiritual, use of parasites, seems to have been invented by no less a personage than the founder of the Dominican order of monks, since it is related in the same work "that the Devil, teasing St. Domingo in the shape of a flea, skipped upon his book, when the saint fixed him as a mark where he left off, and continued to use him so through the volume."

Although we may infer from such personal and therefore very trivial uses of fleas and lice as food, book-marks and taxes, that both saints and savages have occasionally endeavored to make their parasites subserve a useful purpose, it is only within very recent times that what may be properly called an economic use has been suggested for certain parasitic and predatory insects; namely, that of controlling the insects injurious to our crops, forests, domestic animals, stored foods and fabrics. The notion of using predatory beetles in destroying garden pests seems first to have occurred to Boigiraud de Poitiers in France in 184.[1] and in the following year to Antonio Villa in Italy. 3 The latter country also produced the two entomologists Eondani and Ghiliani, who, during the fifties and sixties of the past century, first suggested the use of parasitic insects for similar purposes. Since 1870 this suggestion has taken firmer hold of entomologists, especially in France, Italy and the United States, largely owing to the remarkable results achieved by Riley, Howard and their collaborators in our federal Bureau of Entomology. To mention only a single example, it has been found that the fluted scale (Icerya purchasi), so destructive to the orange, can be controlled by an Australian ladybird (Novius cardinalis), and this control has been successful in California, New Zealand, Cape Colony, Hawaii, Florida, Portugal, Italy, Syria and Egypt. The scale was accidentally introduced into all of these countries and in all of them the beetle, when in turn introduced, showed itself capable of preventing the pest from spreading and destroying the orange trees. This and many similar, though perhaps less striking, cases, have led entomologists to ransack remote regions of the globe for parasites to rear and turn loose on the noxious insects, which, after accidental introduction into our country, increase so alarmingly and do so much damage, owing, in great measure at least, to the absence of the parasites and other enemies that keep them in check in their native environment. The most elaborate experiment of this nature and one which is being followed with keen interest by all economic entomologists, is now being carried on at the Parasitological Laboratory at North Melrose, near

  1. For a fuller account of the work of these and other early promulgators of the use of predators and parasites in combating noxious insects, see Trotter, "Due precursori nell' applicazione degli insetti carnivori a difesa delle piante coltivate," Bedia, V., 1907, pp. 126-132.