14 
CORN AND GRASS. 
prevent them spreading on to useful pasturage or corn-land as far as 
possible. For this purpose firing bands or patches of the dry mountain 
growths is one plan; digging shallow ditches, in which the caterpillars 
are collected in great numbers when on the march and destroying 
them in these, is another. Pigs are stated to be exceedingly fond of 
them, and can be turned on to the ditdies to devour the grubs. Also 
where trenches could be filled with water, or water diverted from 
mountain streams across their onward path, this would do good. 
The usual class of remedies for grub-infested land, such as lime, 
salt, &c., have been, and doubtless would be, of use if the nature of 
the land allowed them to be applied at a paying rate early in the 
attack. But, when established, no remedies except such as are on a 
broad scale, as firing, or excavating trenches, or turning water on, 
appear to meet the widespread nature of the trouble. 
Corn Aphis, Dolphin, or Plant Louse. Aphis (Siphonophora) 
granaria , Kirby ; Aphis avence , Fab. ? 
Aphis granaria. 
1—4, winged and wingless Aphides, nat. size and magnified (3 and 4 discoloured 
from attack of parasite fly) ; 5 and 6, Aphidius avence; 7 and 8, Ephedrus plagiator, 
parasite flies, nat. size and magnified. 
Attack of Corn Aphis has been unusually prevalent during the past 
season, and has been injurious to Oats as well as Wheat. Damage 
from Corn Aphides or Plant Lice has occasionally been reported in 
previous years, but not to the extent in which it appeared last season, 
and, as various inquirers sent regarding it as an attack which was 
