THE BEETLES: ORDER COLEOPTERA 141 



black locust trees. In about ten days these eggs hatch 

 into tiny larvae that excavate slight cells in the bark ; they 

 remain in these cells throughout the winter. Soon after 

 the sap begins to flow the following spring, the larvae be- 

 come active and begin to burrow through the bark into the 

 wood. The burrows that they make are commonly not 

 very long and are enlarged as the insects increase in size. 

 The larvae become full grown in a few months, and change 

 to pupae within their burrows about midsummer. A little 

 later they change again to adult beetles that come forth to 

 feed upon goldenrod flowers and deposit eggs for another 

 generation of borers. 



The characteristic larvae of various wood-boring beetles 

 are very often to be seen when firewood is split up, dropping 

 out of the cylindrical chambers they have burrowed in the 

 wood. They may also frequently be found beneath the 

 bark of fallen trees or in the partially decayed wood of 

 dead stumps. Some species are much more destructive 

 than others, but in general their life histories are quite simi- 

 lar. The Pine Sawyer is a large species that breeds in 

 dead pine trees and often causes losses of millions of 

 dollars in a single year. The Oak Twig Pruner is another 

 widespread pest ; it may commonly be found in fallen twigs 

 under oak trees. 



CURCULIOS AND OTHER SNOUT BEETLES 



Most farmers' boys know how difficult it is to grow 

 plums. From the time the fruit is half grown until it is 

 ripe it continues to fall to the ground, and when examined 

 is found to be wormy and unfit to eat. This worminess 

 is generally due to the insect known as the Plum Curculio, 

 a small, hard-shelled, brownish beetle, which appears among 

 the plum trees in spring. It gnaws holes in the leaves, 



