316 OHIO EXPERIMENT STATION: BULLETIN 332 



BORING INSECTS 



Among the borers are found some of the most destructive shade 

 tree and forest insect pests. Moreover, in the main there is little 

 to be done by way of applying artificial control measures. 



THE LOCUST BORER 



[Cyllene robiniae Forst.) 



Description. — The adult is a slender, long-horned beetle, vary- 

 ing in length from one-half to three-fourths of an inch. The gen- 

 eral body color is velvety-black, beautifully marked with bright, 

 yellow lines extending crosswise of it. The legs and antennae are 

 rich, dull yellow. (See Plate LXII, Fig. 2.) 



The eggs are elongate, snow-white and large enough to be seen 

 plainly with the unaided eye. They are found in crevices of the 

 bark. (See Plate LXII, Fig. 1.) The larva is about three-fourths 

 of an inch in length and decidedly club shaped. (See Plate LXII, 

 Fig. 3.) The pupa is almost as long as the larva is, yellow in color, 

 and is found in the burrows made by the larva. 



Life history and habits. — The beetles appear in September 

 when they may be seen in abundance feeding upon the flowers of 

 goldenrod (See Plate LXIII, Fig, 1) or nervously running up and 

 down the trunks of locust trees searching for a place to lay their 

 eggs. It is while feeding on goldenrod that the average observer 

 most frequently sees the beetle. 



Any roughened area on the trunk of the host is acceptable to 

 the beetle for oviposition, the scars resulting from previous opera- 

 tions being favored situations. The eggs may be deposited in clus- 

 ters or may be laid singly. Frequently a part of the egg remains 

 exposed. 



The eggs soon hatch and the tiny larvae bore their way into 

 the bark, feeding upon the soft inner portions. In this situation 

 the small larvae pass the winter. In the spring they resume feed- 

 ing and boldly eat their way into the hard heartwood of the host. 

 A knot or enlargement forms about the entrance hole of the feeding 

 larva and in time the trunk of the host becomes much deformed. 

 See Plate LXIII, Fig. 2, for a typical section of an injured tree. 



Larval growth is completed by midsummer, the insect pupates 

 within the larval burrow and the adults emerge in September. 



Nature of work. — As the name indicates, this is a true boring 

 insect. It attacks those parts of the host which are covered with 

 roughened bark; thus on young trees the work is confined largely 

 to the trunk, while on large ones the limbs also are affected. Heart 



