298 



Beetles 



1 



at the base of young corn-plants, and at night bore little round holes into 

 their stems. The larvae live in the stems of timothy, sedges, or bulb-rooted 

 grasses, pupating in fall or early spring. To the genus Calandra belongs 

 the destructive rice-weevil, C. oryzce, \ inch long, blackish to pale chestnut, 

 which attacks all kinds of stored grains and is especially injurious in the 

 southern states to rice, and the granary-weevil, C. granaria, % inch long, 

 dark brown, also common in grain-bins. Both these species have been 

 widely distributed by commerce, and by their rapid multiplication and the 

 concealment afforded them by the grain often attain such abundance as 



to cause great loss in mills, breweries, 

 and elevators. The preventive remedy 

 is cleanliness and the rapid removal of 

 the stored grain. They prefer dark 

 places, therefore a flood of sunlight 

 will prevent their rapid increase. In 

 bins that can be made nearly air-tight 

 these pests may be killed by the fumes 

 of carbon bisulphide. 



One may often see in the woods the 

 curious hieroglyphics of the engraver- 

 beetles (Scolytidae). Where bark has 

 been torn from a tree -trunk both 

 the exposed trunk-wood and the inner 

 surface of the stripped-off bark reveal 

 the tortuous branching mines or tunnels 

 of the Scolytidaa. A common way of 



,, r /- making these tunnels is as follows: The 



FIG. 407. The qumce-curcuho, Cono- 



trachelus cratagi. (After photograph beetles (a male and a female together) 

 by Slingerland; natural size and en- burrow from the outside through the 

 lareed.) 



thick rough outer bark, usually leaving 



a little betraying splotch of fine sawdust, to the inner live bark or sap- 

 wood; here the pair turn, keep to this live sap-filled region, laying their 

 eggs in masses or scattered along a tunnel. Soon the larvae hatch, where- 

 upon each digs a tunnel for itself, all of the new larval mines branching out 

 from the original tunnel made by the parent beetles. When full-grown 

 the larva digs a cell at the end of its tunnel and pupates in it. The issuing 

 beetle burrows its way out from the tunnels and is soon ready to begin a new 

 mine. But there is much variation in the mining habits of the various species. 

 The beetles are small, often microscopic, the larger ones rarely more than 

 \ inch long. They are brown to blackish, with stout, nearly cylindrical 

 hard bodies, the hind end of the body usually obliquely or squarely truncate, 

 and the head short, bent downward, and so covered by the thorax as to be 



