
Figure 6,--Basic light trap, installed near Oxford, N.C,, is representative of 
more than 360 such traps operated in 1962-64 to control tobacco hornworms, 
produce a substance attractive to the males 
(Allen et al., 1962), were kept in small cages 
near light traps, The traps were located at 
least a mile apart and varying numbers of 
females rotated between locations, Table 2 
shows the results of the first experiment, 
There was a significant increase in both male 
and female catches, For unknown reasons, the 
200 
increase in female catch was not repeated in 
later tests, but male catches were always 
greatly increased, Figure 7 shows the effect 
of increasing the number of virgins, Ifitis as- 
sumed that the catch of the light trap alone is 
100, then the regression equation will be Y = 
100 + 94,3 X. That is, one virgin female will 
approximately double the catch of a light trap; 
