188 FRUIT INSECTS 



The round holes (Fig. 184) nearly as large as a lead pencil 

 in the base of the trunk of trees infested by this round-headed 

 borer are the exit holes of the beetles which have developed 

 from the grubs or borers. The beetles emerge mostly at night 

 and remain hidden and inactive during the day. Even in 

 northern localities some of them emerge in April, many of them 

 in May and June, and there are records of their emergence in 

 different localities during the next two or three months. Prob- 

 ably most of the eggs are laid in June, but oviposition may 

 continue to September even in the same locality. The smooth- 

 shelled, pale, rust-brown egg measures an eighth of an inch in 

 length, by one third as wide and is slightly compressed. The 

 eggs are laid in the bark, usually near the ground. The female 

 beetle first makes an incision or slit in the bark, probabl}^ 

 with her sharp, horny jaws, but one observer says it is made 

 with the ovipositor. The egg is deposited in the incision, 

 sometimes at the bottom next to the wood, but g^erally in 

 an opening made in one side of the cut halfway through the 

 bark, nearly a quarter of an inch from the cut. It is then 

 covered with a gummy fluid that sometimes fills the slit and 

 hides the egg, but some observers report that the eggs are 

 easily found. From eggs laid June 15, larvae hatched in about 

 three weeks in New Hampshire. 



The young larvae soon tunnel through the bark (Fig. 182) to 

 the sapwood in which they work for a year or more, often ex- 

 tending their shallow flat burrows downward below the surface 

 of the ground and remaining dormant in winter. The borers 

 begin work early in the spring, often in March or April, and 

 during the second year of their growth they extend their burrows 

 farther into the solid wood, sometimes going through and girdling 

 young trees. The tunnels often extend upward and downward 

 at various angles in the tree for several inches. Most of the 

 sawdust-like excrement of the grub is packed in its burrow, but 

 some of it is pushed out through small holes eaten through the 



