ROUNDHEADED APPLE-TREE BORER. 7 



were useful in other ways in preventing the disturbance of the in- 

 sects. A larger form of cage was made by stretching wire over a 

 light wooden frame 2 by 2 by 4 feet in dimensions. Cages of this 

 type were used to set over apple trees 3, 4, or 5 years of age that had 

 been headed low and pruned in for the purpose. When in place 

 these cages were mounded slightly with earth at the bottom to pre- 

 vent the escape of the beetles and were secured from wind by being- 

 attached with screws to posts driven into the ground at the corners. 

 In these cages many beetles were confined over growing trees, and, 

 so far as could be observed, lived lives comparable in length with 

 those in the field. Several other cages of larger size were built over 

 clumps or short rows of young apple trees. Some of these cages were 

 20 feet in length by 8 feet wide and 8 feet high. They were pro- 

 vided with tight-fitting doors large enough to admit a man and were 

 used for observations on the various stages of the borer and for test- 

 ing control measures. 



THE EGG AND OVIPOSITION. 



THE EGG. 



The egg (PL IV, B, C, E) when first deposited is yellowish 

 white, assuming a darker shade within a few days. It is 3.5 to 4 mm. 

 in length by 1 to 1.5 mm, in width, slightly flattened, both ends 

 tapering to rounded points, the shell tough and plastic, bending 

 somewhat in conformity to the space which it occupies. There is 

 considerable variation in size and shape. 



THE OVIPOSITION PROCESS. 



Egg laying usually begins a week or ten days after the female 

 beetles leave the wood. In preparing to oviposit, the female as- 

 sumes an oblique position on the bark (PI. Ill, A) and with her jaws 

 makes a slightly curved slit in the bark 4 or 5 mm. in length, and 

 usually extending parallel with the grain of the bark. (PL IV, A.) 

 After the incision is completed, the beetle turns, inserts the tip of 

 the ovipositor into the opening, and with considerable effort forces 

 it into the tissue, usually between the bark and wood. (PL IV, 

 B, C.) The ovipositor is inserted at about the center of the slit 

 made with the mandibles and is extended under the bark in a direc- 

 tion at right angles to the slit. The egg is placed with the end toward 

 the slit and from 1 to 2 mm. from it at the nearest point. After the 

 ovipositor is withdrawn a small mass of clear, gelatinous liquid is 

 ejected into the hole, which dries and seals the egg chamber. Two 

 or three minutes are spent in making the initial slit and twice that 

 time in inserting the ovipositor, laying the egg, and sealing the 



