The following wavelengths were compared with each other in all possible com- 

 binations : 



Milli- Milli- 



micron micron 



315 435 



340 485 



365 515 



385 545 



405 580 



A Beckman Model DU spectrophotometer was modified for use as a monochromator 

 to provide the various wavelengths at one end, and the Bausch and Lomb monochromator 

 was used on the other end as in Test Series I. Slits of both monochromators were ad- 

 justed for a bandwidth of 3.3 m/i . It was found necessary to reduce the area of the quartz 

 diffusing plates to lj" x 1^" in order to accommodate the radiation pattern from the 

 Beckman DU. 



As in Test Series I, 3- and 4-day old moths were used and from 30 to 116 moths 

 were used in each test (average number of 68 moths per test). Including reruns and tests 

 under blackout conditions, a total of 131 tests were conducted, involving a total of 

 8,927 moths. All tests were initiated after 1,330 hours. The detailed test procedure for 

 this test series was identical with the procedure as outlined in Test Series I. 



Intensity Studies: The response curves obtained for Test Series I and II indicated that 

 three wavelengths (365 m/i, 405 mfi, and 515 m/U) would be of principal interest in fur- 

 ther work on the response of the pink bollworm since these were the wavelengths of 

 maximum and minimum responses. The study on the effects of the use of higher intensity 

 levels at these wavelengths was considered important, because other workers have 

 put much emphasis on the importance of intensity effects on wavelength response. Pre- 

 liminary tests were made in the small-test tunnel at higher intensity levels (higher than 

 that used for Test Series I and II) but no reproducible results could be obtained. It was 

 thought possible that the verified small size of the tunnel was the main factor contributing 

 to this variation. This was verified by exploratory investigations in the larger test 

 chamber used by Stermer"in his work with stored-products insects. This 4' x 6 1 x 14' 

 chamber was made available for use in these tests and was found to be quite satisfactory 

 for tests at the higher intensity levels. As in the tests of Series II, energy from the 

 Bausch and Lomb monochromator and the Beckman DU spectrophotometer was presented 

 to the insects through ground quartz diffusing plates. For this test series the image 

 size was masked down to a size of j" x 1". Under these conditions it was found that 

 the approximate minimum intensity level feasible for use was at a level 20 times greater 

 than that used in previous tests in the small tunnel. An experiment was designed for 

 comparison of 365, 405, and 515 m/x at intensity levels of 20, 40, and 80. The procedure 

 for these tests was somewhat different from that used in Test Series I and II. The 

 moths were given no dark conditioning period prior to exposure to the two sources 

 of radiation. Also, owing to the large numbers of moths used per test, only one test- 

 started late in the afternoon and continued until the following morning- -was conducted 

 each day. Insects attracted to the sources were collected in modified New Jersey 

 mosquito traps. 



This test series comprised 36 tests. Analysis of results was based on a total of 

 4,246 moths that responded to one or the other of the sources. 



■ See footnote 9. 



17 



