Insect Ravages in Woodlands. 



167 



91. Vertical Section through 

 the Burrows of the Hostrichus 

 lineatus. 



emerge through holes eaten in the bark, and come forth as perfect 

 insects. 



664. Climatic vicissitudes have great 

 influence upon the multiplication or 

 decrease in the number of insects. A 

 very hot and dry season may favor an 

 increase, or an unusually cold, wet, and 

 backward one may destroy them. 



665. Insectivorous birds do much 

 to keep injurious insects in check, and 

 where there is an abundance of this 

 food, they will sometimes appear in 

 great numbers. The presence of these 

 birds is therefore to be encouraged ; 

 and as groves and belts of timber are 



multiplied, the conditions favoring their coming and sojourn, to the 

 benefit of our grain and fruits, are increased. For these reasons 

 they should be strongly protected by efficient game laws, and by 

 public sentiment, against their destruction, or the disturbance of 

 their nests. 



665J. In some countries, as in France, the importance of protect- 

 ing birds is taught in the schools, and the children are shown how 

 to distinguish the useful kinds of birds, small animals, reptiles, and 

 insects from those that are injurious, and the best means for pro- 

 tecting the former, and of destroying the latter. Little " Protec- 

 tion Societies" are organized among the children, for preventing in- 

 juries to birds and their nests, and various means are devised to 

 impress the young with correct ideas concerning the interests 

 depending upon the allies of the field. 



666. In nurseries, gardens, orchards, and parks, we may some- 

 times adopt measures for the destruction of insects, when they ap- 

 pear in unusual number, by some kind of poisons, such as Paris- 

 green, London-purple, white-hellibore, etc., but where they invade' 

 a whole forest, and especially when they occur in regions remote 

 from settlements, we can do nothing, and must await the operation 

 of natural causes for restoring the balance, through the natural 

 agencies of climate and the antagonism in insect life. 



667. In some countries this can b'e done by costly methods, such 

 as cutting down the infected trees, and burning the tops and the 



