INSECTS AND PLANTS 69 



and the velocity of the wind over fifteen miles an hour. In 

 gusty weather one may observe leaves caught by the wind 

 and carried several hundred feet into the air ; there they 

 may be, and often are, brought into contact with the strong 

 currents of the upper air and carried several miles before 

 falling to earth. Observers are agreed that the same 

 thing occurs to the first-stage larvae, when they are sus- 

 pended from the trees by the silk which they spin, though 

 actual proof is wanting. If the surmise is correct, it would 

 account for the, at present, unaccountable spread of the 

 gipsy moth to new territory. 



Though probably every family of insects contains one or 

 more species that have earned an unenviable notoriety, on 

 account of the havoc that they cause, either among man's 

 crops or his livestock, certainly none contains so many 

 injurious species as the family Coccidce, or scale insects, 

 the most notorious member of which is the San Jos6 scale, 

 Aspidiotus perniciosus. Although of Chinese origin, as 

 we shall see later, this insect was first encountered in 

 America, at San Jose", California, in the early 'seventies. 

 In less than twenty years, from the time of its first 

 appearance in Western America, it had spread to the 

 Atlantic seaboard and into Canada, and there are now very 

 few fruit-growing districts in the North American conti- 

 nent, within the climatic range of the insect, where it has 

 not gained a permanent foothold. 



With the thoroughness that is characteristic of the 

 Americans, in all matters appertaining to economic ento- 

 mology, it was decided to discover, if possible, the original 

 home of the scale with the object of finding some control 

 insects, either parasitic or predatory. Suspicion having 

 fallen on Japan and China, Mr C. L. Marlatt, of the United 

 States Bureau of Entomology, decided to visit these countries 

 in 1901. Japan was first explored, and in spite of the fact 

 that practically every house in that country has a little 

 garden in which are single examples of cherry, plum, or 



