INSECTS INJURIOUS TO FOREST TREES. 175 



quassia chips, and soap suds ; and others dusted over the insects, 

 as snuff, soot, quicklime, etc., but none are so effective or easily 

 applied as tobacco liquor. I find that one gallon of tobacco juice, 

 of the ordinary strength sold in shops, to six gallons of water, is 

 sufficiently strong to kill all aphides, if applied with force through 

 a syringe or engine, so that every insect is thoroughly wetted with 

 it ; the operation is most effective in hot, dry weather. 



There are some insects which ought to be protected and encour- 

 aged whenever possible, as they are deadly foes to all aphides 

 — the larva of the ladybird (Coccinella bi-ptunetata and septem- 

 punctata), the pearly moth (Hemerobius perla), the bee-fly (Syrpihus 

 parasitica), and several species of Aphidius, ichneumon or lion flies, 

 all of which devour aphides with the greatest avidity. The ear- 

 wig and ant are also said to be bitter enemies to aphides, but as 

 they are themselves addicted to mischief, they ought not to be 

 encouraged. There are also many birds which devour vast numbers 

 of aphides as well as other insects, and all such birds ought to be 

 strictly preserved and encouraged to increase as much as possible 

 in our forests and plantations. If the insectivorous birds were 

 more plentiful in the country, we would be less troubled with the 

 ravenous attacks of insects upon vegetation. 



In hot and dry summers, trees and shrubs suffer severely from 

 red spider (Acarus telarius), one of the mite family, which often 

 infests limes, elms, poplars, and other deciduous trees, so as to 

 cause the leaves to turn a russety brown, and fall off prematurely, 

 weakening and exhausting the tree of its sap, and preventing the 

 season's growth from arriving at maturity. As the extent of the 

 ravages of the red spider is much influenced by the dryness or other- 

 wise of the season, it is hardly necessary to go into a lengthened 

 detail of its nature and habits. I need only remark that it detests 

 cold and wet, and if young plants are infested with it, a good 

 syringing with soap suds is the best remedy I have tried. The 

 spider is very tenacious of life in dry, warm weather, and the syr- 

 ingings will have to be repeated so long as the insects are seen to 

 be on the move. If the plants are dry at the root, a heavy water- 

 ing will be beneficial to them and assist in dispelling the spider. 

 Shovdd specimen conifers be attacked by spider, as they often are 

 in dry weather, especially firs and spruces, the same treatment 

 will clean them, that is, a heavy watering at the root, and a 

 thorough washing overhead with an engine. 



Of the numerous varieties of the coccus or scale family, some 



