172 



Classification of Insects : Colcoptera. 



ditions for their increase are multiplied, as in case of many trees 

 being prostrated by a gale, they increase in enormous quantities, and 

 destroy whole forests. In such cases, they appear to attack per- 

 fectly healthy trees. The first of these (B. typoyraphicus) does the 

 most harm, and is found chiefly in and under the bark of the trunk 

 and large branches. The preceding engraving represents a set 

 of burrows made by the larvae hatched from the eggs of one insect, 

 and an enlarged view of the insect itself. 



683. The burrows of the Bostrichus calcographus are generally 

 found at the same time, and upon the same trees as those of the 

 preceding species, but only upon the smaller branches. The only 



96. Burrows of the Bostrichus chalcngraphus, with the Insects 

 of Natural Size. 



effectual remedy known against these insects, is that of cutting down 

 the trees, and peeling and burning the bark. In an invasion of 

 these insects in the Jura region in South-eastern France, following 

 as one of the consequences of a storm that happened in November, 

 1864, it became necessary from 1867 to 1873 to carefully examine 

 every tree in a forest, and to cut down every spruce that showed 

 signs of the insect, and to peel and burn the bark upon over 



