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THE CANADIAN ENTOMOLOGIST 



such means of controlling insect pests. A far more important 

 consideration has to do with the proportion of males and females 

 secured by light traps. Take FelHa venerabilis for instance; this 

 is one of our commonest cutworm moths, which is freely attracted 

 to light, yet of the 192 specimens so secured all were males. 

 Other species, with few exceptions, show very similar results. 

 The Red-backed cutworm {Euxoa ochrogaster) , while enticed to 

 light on favourable occasions, was entirely absent during the three 

 years experiments were carried on, though examples were secured 

 close at hand at the time and larvae had previously been very de- 

 structive. The proportion of hymenopterous parasites taken at 

 light is also an important factor to be reckoned with. Lastly, 

 we have to take into consideration the fact that at least some of the 

 female moths collected will have already deposited a proportion 

 of their eggs. 



Below is given a table showing the records of captures for August 

 and September for three years past — ending 1917. The collec- 

 tions of individual nights have been lumped for convenience. Two 

 traps were used in the work, one of the usual search-light pattern, 

 and the other a trap devised by my brother Stuart in which three 

 sides were exposed to the light. These traps were placed in dif- 

 ferent localities where cutworms were known to have occurred. 

 They were put out on practically every suitable nigTit during the 

 three seasons. The July results were too small to make them 

 worth recording. . 



