20 BULLETIN HOT, U. S. DEPARTMENT OF AGRICULTURE. 



Healthy wood cut, felled, or broken by the wind and down from 

 two weeks to six months seems to be preferred by the beetle when 

 she excavates the egg gallery. If there is none of this accessible, she 

 will enter logs or stumps from which she has emerged or attack 

 other dead or dying material. She does not like to enter wood killed 

 by fungi or other slow-killing timber diseases. 



Lt ngth of life. — The females live longer than the males. In the 

 cages with sections of wood the males lived from 10 to IS days and 

 the females from 30 to 44 days. In the cages, on the cables where 

 there was no wood, both sexes died in from 5 to 7 days. 



CONTROL EXPERIMENTS. 12 



TESTS AT FALLS CHURCH, VA., 1918 AND 1919. 



In 1918 a large quantity of California oak (Quercus agrifolia) 

 (500 pounds) infested with Scobicia dcclivis was shipped by Mr. 

 P>nrke from Los Gatos, Calif., to the forest insect field station of the 

 Bureau of Entomology at Falls Church, Va. This was placed in a 

 large, specially constructed cage. In June adults began to emerge 

 and some were caged in glass cylinders with covers of test-sheet 

 lead. In some cases the smooth lead was marked — criss-crossed with 

 a nail so that the beetles would not slip; in other jars small strips 

 of copper were nailed to the lead so that an arch was formed to en- 

 able the beetles to get a footing on the smooth lead and brace them- 

 selves to bore. Adults so caged, when they lost their footing, often 

 spun around the smooth lead on their heads (partly flying) in 

 attempting to regain a foothold. They did not bore through the test 

 lead sheathing under these conditions, and all the efforts to assist 

 the beetles failed. 



Other adults were left to fly freelv in the large cage to attack the 

 suspended cables of different alloys hung on various types of rings, 

 wire and tape. (Fig. 15.) Several pairs of these adults infested the 

 corks from 100-millimeter vials, constructing their galleries in the 

 corks. 13 The beetles entered the heavy beams (Southern yellow pine) 

 supporting the cage and the old California laurel limbs. They did 

 not attack the suspended cables. 



Sheet lead of different alloy composition was tightly wrapped 

 around infested sections of logs, the sides being overlapped and 

 nailed into close contact with the wood. (PL VII, Fig. 1.) The 

 ends also were covered. Many adult beetles bored through double 

 thickness of No. 3 alloy lead (99 per cent lead, 1 per cent antimony) ; 

 Xo. 2 (95 per cent lead, 4.5 per cent antimony, 0.5 per cent tin), and 



12 These control experiments were made in active cooperation with the American Tele- 

 phone & Telegraph Co. and associated companies, who supplied the metals, alloys, etc., 

 and installed the test cables in Virginia and California. 



"There are records of the adults entering a loaf of bread in California and a Douglas 

 fir window sill in Oregon. 



