y4N ECONOMIC EXTOMOLOGY. 



These beetles differ from all the other weevils in their cyHn- 

 drical form and very short snout, which is scarcely more than a 

 slight prolongation of the head, and they are usually of small 

 size, most of them not exceeding one-eighth of an inch in length. 



Fig. 245. 



Cala?idra granaria.—a, adult ; b, larva ; c, pupa ; d, C. oryza, adult. 



Scolytus rugulosus, the "fruit-bark beetle," is, perhaps, the 

 best known, and certainly the most important economically, 

 attacking deciduous fruit-trees of almost all kinds. The black 

 parent beetles appear in early spring, and bore little round holes 

 through the bark to the sap-wood. They then make a central 

 burrow, on each side of which little notches are made to receive 

 the soft white eggs. The larvae hatch very soon, and at once 

 begin to make little burrows of their own, diverging as they 

 move from the parent channel, and gradually enlarging them as 

 they increase in size. When full grown they form a slightly 

 enlarged chamber, in which they pupate, and when they trans- 

 form to beetles, make their way out through little round holes 

 in the bark. The whole period of development does not exceed 

 a month, and there may be several broods during the summer 

 from the same tree, the numerous galleries eventually girdling 

 and killing it. 



