160 TlMEHRI. 
ment for the year 1881, by Charles V. Riley (1882), both issued from 
the Government Printing Office at Washington. Both may be 
consulted with advantage, and the more so as the two authors did 
not work in concert, and their ideas are not always identical in the 
means proposed. In Professor Riley's report he has been aided by the 
practical experience of Mr. H. S. Hubbard, who devoted himself 
specially to the subje6t. In the Southern United States the attacks of 
" scale" on oranges has become of national importance ; and experience 
there, and in British Guiana should be nearly identical, although the 
particular species of scale insect injurious in the British colony does 
not appear, to have been observed in the States. 
Of mechanical measures, one of the most importance is that of 
brushing the part of the trees infested with a brush sufficiently strong 
to remove and destroy the scales without injuring the bark. It 
must rest with orange planters in the districts affected to consider 
how far this can be successfully done, in which the height of 
the trees and the comparative freedom from scale of the leaves and 
fruit must be taken into consideration ; cutting back or lopping and 
burning the affected portions of the tree might also be tried, though 
this naturally checks the supply of fruit until new wood is produced. 
Stimulating by powerful manures so as to enable the trees to outgrow 
as it were the attacks of the insect, has also been recommended, but it 
is possible that this may tend to an over-production of young wood and 
leaves, and a diminished supply of fruit. Finally, there is the radical 
remedy of stamping out by destroying all the infested trees and begin- 
ning again. This might occasion ruin or severe loss to poor planters, 
and would probably require a Governmental subsidy to the parties 
affected for a considerable time. In connection with this it is desirable, 
whether the planters should not ask themselves if the trees have become 
naturally in an unhealthy condition, and the soil exhausted through 
continuous growing of the same trees on the same ground. It appears 
to me possible that rotation of crops may be as necessary in the case of 
cultivated trees or shrubs as it has been proved to be with cereals and 
herbaceous plants, and on this point I think the American reports before 
alluded to, are not sufficiently explicit. 
The number of the inseaicides that have been tried is very great. Some 
of them have proved impraaicable owing to their destroying both the 
plants and the inseas, others again have proved only partially success- 
frl or have been very difficult of application or too expensive. It seems 
