328 OHIO EXPERIMENT STATION: BULLETIN 332 



In the fall of the year it will be noted that twigs a foot or more in 

 length are dropping from the tree under attack and these twigs upon 

 examination will be found with the end so neatly and squarely 

 smoothed off as to appear cut with a sharp chisel. Upon examina- 

 tion the pruned twig will be found to bear a tunnel and within the 

 tunnel is a slender grub, white in color with the exception of the 

 jaws which are brown. The adult is a slender grayish-yellow some- 

 what mottled beetle, a little over one-half of an inch in length. (See 

 Plate LXX, Fig. 1.) 



Life history and habits. — Doctor Felt has recorded the life his- 

 tory and habits of this species as follows: "The adult is said to 

 deposit an egg in July in one of the smaller twigs. The young larva 

 feeds for a time in the softer tissues under the bark, packing its 

 burrow with castings and working toward the base of the twig. 

 Later it bores along the center of the limb, making a more or less 

 oval channel. In the early fall our borer quietly eats away a large 

 portion of the woody fiber, plugs the end of the burrow with castings 

 and waits for a high wind to break off the nearly-severed branch. 

 In this manner the larva reaches the ground in safety. Late in the 

 fall or in the early spring the change to the pupa takes place and 

 the transformation to the perfect insect occurs in the spring, the 

 beetles emerging from the limbs in June and continuing abroad until 

 September. Occasionally the insect completes its changes in the 

 portion of the limb remaining on the tree; it as a rule drops with 

 the severed branch." 



Nature of work. — As the name indicates and in the manner the 

 previous paragraph depicts the maple and oak twig pruner is a 

 destroyer of the twigs and small branches of the host, and this 

 process constitutes the prime injury inflicted by the species. In a 

 secondary manner, however, this twig pruner is injurious because 

 the fallen branches attract other wood-boring beetles, some of 

 which may attack the living wood of the host. Ordinarily, the prun- 

 ing of the twigs is no very great detriment to the tree since the 

 twigs rarely are destroyed in any very great numbers. However, in 

 December, 1917, the writer observed extreme injury to elms along 

 the Arkansas River in southern Kansas where at least 50 percent 

 of the smaller branches were pruned and had fallen to make a veri- 

 table mat beneath the tree — apparently the work of this species — 

 although I did not have an opportunity to rear the adult form. 



The falling of the pruned twigs on lawns and in parks some- 

 times constitutes a source of considerable annoyance. It is no 

 uncommon thing to hear that squirrels are blamed for the work. 



