HISTORY IN CALIFORNIA AND THE WEST. 15 
frontiers of China proper. Beyond the great wall on the north and 
west lies Mongolia, consisting chiefly of the vast Desert of Gobi. To 
the northeast, and separating the region from Manchuria and Korea, 
is the eastern Gobi Desert. To the south and east lies the great alluvial 
plain, the product of centuries of mud carried down by the Yellow 
River, a region where cereals only are grown. These are all effective 
barriers, and especially so when considered in connection with the 
political conditions of the past. We have, therefore, as the original 
home of this insect a naturally shut-off area from which it could not 
easily escape under the conditions prevailing up to our own times. 
The means by which the San Jose scale came from China to America 
is a matter of interest. As previously stated, it is believed that this 
pest reached California on trees imported by the late James Lick. 
It is the writer's belief that Mr. Lick imported from China, possibly 
thru Doctor Nevius, with whom he was probably in correspondence, the 
flowering Chinese peach, and brought with it the San Jose scale to his 
premises. Undoubtedly this scale insect came to this country in some 
such way on ornamental stock from China. 
RECORD OF THE SPREAD OF THE INSECT. 
No attempt will be made to trace the details of the later extension 
of the San Jose scale, but the earlier history of this scale in the 
United States is well worthy of record as is also a summary at least of 
the means by which it became so widely and disastrously distributed 
so shortly after its first appearance on the Atlantic side of the 
Continent. 
HISTORY IN CALIFORNIA AND THE WEST. 
The spread of the San Jose scale from the point of original infesta- 
tion in the San Jose Valley was somewhat rapid, its area increasing in 
every direction, but more rapidly toward the north and the west. By 
1873 it had become a serious pest in orchards which had direct con- 
nection with that of Mr. Lick, and in 1880, when Professor Comstock 
studied it, he reported that he had never seen any other species so 
abundant and injurious as this was in certain orchards. As reported 
by Mr. Coquillett, it had extended as far west as San Francisco by 
1883, but it had not reached important deciduous-fruit districts in 
southern California three years later. Prior to its reaching the East 
in 1886 or 1887 it had slowly extended its range on the Pacific coast 
and in States west of the Rocky Mountains, including California, 
Oregon, Washington, and Idaho on the north, and Nevada, Arizona, 
and New Mexico on the south. In the early nineties it had penetrated 
into British Columbia. 
8449— No. 62—06 2 
