170 THE CANADIAN ENTOMOLOGIST. 



wax, the shoot, however, not being severed until after it had united with 

 the stump, when it was cut off just below the juncture, thus greatly 

 facilitating the growth of the graft, as it could draw its nourishment from 

 the parent stock until it had firmly united with the new. These old 

 stocks or stumps were much more seriously infested with the San Jose 

 scale than the younger wood, averaging from one to six individuals to 

 the square inch of bark surface, but extending upwards on the young 

 growth well toward tlie extremity. On the old wood many of the scales 

 were dead, but there were plenty of live ones and it was impossible to 

 determine whether or not the dead had been parasitized, partly eaten by 

 carnivorous enemies, or crushed in the handling of the stock, but that 

 this was a direct importation does not admit of a doubt. 



Mr. Cockerell thinks that the San Jose scale may probably be a 

 native of the more or less elevated regicjns of Japan, the species of 

 scale insects found there near the sea level seeming to belong to oriental 

 tropical types. It was impossible to learn the exact locality where the 

 stock examined by me had been propagated, but there were certainly no 

 indications of immunity to the attack of this scale, though the trees 

 might, perhaps, have withstood the attack better and survived longer, 

 but, judging from all that could be observed from the actions of the scale 

 on the importation of 1896-7, without the influences of natural enemies, 

 it would spread as rapidly on a tree from Japan as it would on one from 

 America, and this raises the question as to why, if it occurs in Japan, as 

 it certainly does, this scale does not become as destructive there as with 

 us in America. If this immunity is not due to resistive powers of the 

 stock, and I certainly believe, from what I saw in these cases, it is not, 

 then the protection must come from the influences of natural enemies, 

 which is of itself the best possible proof that Japan is the native home of 

 Aspidiotus perniciostis, and that we have a case parallel with that of the 

 introduction of the Cottony-cushion scale, Icerya purchasi, into California 

 from Australia. We have imported the San Jose scale and left behind ' 

 its natural enemies that hold it in check in Japan, and while we cannot 

 tell just what these enemies are, if the scale is a native of that country we 

 have probably been importing it for years, and in that case, if the enemies 

 were of a fungous nature, or internal feeders, we should have gotten them 

 with their host insect long ago. It seems probable, then, that these 

 enemies, or at least the one that is holding this scale in check, is one 

 that is easily separated from its food and has for this reason been left 



