ROUNDHEADED APPLE-TREE BORER. 9 



litter, or water sprouts, and that trees so surrounded are more likely 

 to be injured by borers than those having trunks exposed to the full 

 light. Observations made by the writer, however, indicate that the 

 beetles prefer to oviposit in the sunlight rather than in the shade. 

 In one case 609 borers were removed from an orchard of 6-year-old 

 apple trees which was located on a hillside having a general slope to 

 the southwest. The trunks of the trees were long and one side re- 

 ceived the unobstructed sunlight during a greater part of the day. 

 The oviposition scars in which the borers hatched were found and 

 those situated on the sunny side and shady side of the trunks were 

 counted separately. As nearly as possible, each side was made to 

 include half the circumference of the trunk. Of the 609 oviposition 

 scars which were located, 393 were on the sunny or exposed side and 

 216 on the shaded side. The fact that about 65 per cent of the eggs 

 had been laid on the more exposed side of the trees indicates that 

 mulches of straw or hay placed around trees or the shading of the 

 trunks by low branches does not attract the beetles, but rather 

 repels them. 



OVIPOSITION IN CAGES. 



Other workers with this insect seem to have had but little trouble 

 in inducing caged femlale beetles to oviposit in apple twigs, in sec- 

 tions of apple branches set in the ground, and even in apple fruits. 

 The writer, however, has never been able to get a normal frequency 

 of oviposition in any but growing trees. At one time 15 pairs of 

 beetles were confined separately in roomy cages for a period of 17 

 days. Fresh apple branches, about an inch in diameter, were set in 

 the ground daily in each cage. Although this was kept up from May 

 31 to June 17, a time when egg laying in the field was at its height, 

 only 17 eggs were secured in the branches and 10 of the 15 females 

 failed altogether to oviposit. The cages with the beetles were then 

 removed and placed over small growing apple trees, whereupon 

 oviposition began freely and at once. Attempts to induce caged 

 females, to oviposit in other than growing trees were made frequently, 

 but never with entire success. 



OVIPOSITION PERIOD. 



As an example of the period of time over which eggs are de- 

 posited in a given locality, observations made in 1914 may be cited. 

 During that year the first female issued on May 23. Eight days 

 later she paired with a male and on June 4 laid her first eggs. No 

 record was obtained of the last egg of this individual but other 

 females continued to oviposit until August 1, the entire egg-laying 

 154187°— 20— Bull. 847 2 



