38 



INSECTS. 



BOBBR. 



Fio. 28. 



any danger tkreatened. 



on the peach. The 

 writer cannot rememher 

 ever having seen them 

 upon the pear. 



The two-stbiped 

 Sa'perda biidttata. This beetle 

 is very destniotive to young apple 

 trees, and sometimes attacks the pear 

 and quince. It does its work so sUently, 

 and removed from observation, liiat fine 

 orchards have been entirely ruined 

 before suspicion was entertained that 

 Fig. 28 represents the beetle or perfect 

 insect and the grub from which it is produced, or the same insect 

 in the larva state. The perfect insect is light brown on the upper 

 side, marked with two chalky-white stripes, running lengthwise 

 of the body ; the under side, the face, the antennse, and the legs 

 are white. It is usually about three quarters of an inch long, 

 moving about at night and remaining concealed by day. During 

 the months of June and July the females deposit their eggs upon 

 the bark of the tree, near the root, at that part known as the 

 collar of the tree. Here the bark is softer than at any other 

 place on the trunk. From the eggs are hatched little fleshy 

 whitish grubs without feet, which cut through the bark, and, on 

 reaching the sap-wood, excavate a round, smooth cavity, about 

 the size of a silver doUar, immediately under the bark. At the 

 bottom of this cavity it makes a hole, out of which it casts its 

 excrements, which appear like very fine sawdust. At this stage 

 of its existence its presence can be readily ascertained by searching 

 for this dust on the ground, just around the trunk of the tree. 

 When the larva has become about half grown it ceases to cast the 

 dust out of this hole, but proceeds to fill up the cavity it had 

 made, at the same time boring a passage or gallery upward into 

 the heart of the tree. This gallery is continued upwards, of 

 variable length, sometimes not more than two inches, and some- 



