432 THE POPULAR SCIENCE MONTHLY 



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 fab- 

 rics. The notion of using predatory beetles in destroying garden pests 

 seems first to have occurred to Boigiraud de Poitiers in France in 184.3 

 and in the following year to Antonio Villa in Italy. 3 The latter coun- 

 try 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 

 Rile3 r , Howard and their collaborators in our federal Bureau of Ento- 

 mology. 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 acci- 

 dentally 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 entomolo- 

 gists 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 



3 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. 



