THE CANADIAN E:nTOMOLOGIST /O 



Micro-lepidoptera, comparatively harmless. Macros and 

 numerous small insects of doubtful economic value are not in- 

 cluded, though collected in considerable numbers. 



Comparing the August catch with that of September it will 

 be observed that there is generally an increase in the proportion 

 of females in the latter month and a falling off in the males. This 

 is doubtless due to the males being more active soon after emerging 

 whereas the females become more so at the period of egg-laying. 

 It will be noted further that the total number of moths collected 

 only exceeds the number of useful insects taken by 196 speci- 

 mens, or including the tipulid flies, 206. 



Another point to be considered is that while the moths in- 

 cluded in this table are all the parents of cutworm-like caterpillars 

 by no means all are recognized as of economic importance. Thus 

 we might reasonably leave out Eiixoa ridingsiana, qtiadridentata, 

 criddlei, redimicula and Feltia robustior. 



Male insects seem to greatly exceed the females in nearly all 

 orders attracted to lights, and the species of Ichneumonid flies are 

 no exception to this rule. The Braconid flies, however, show a 

 greater proportion of females attracted though males still pre- 

 dominate. , 



With reference to the destruction of June-beetles (Lachno- 

 sterna spp.) by means of light traps, the writer conducted a number 

 of experiments relating to this subject in 1914, and it was found 

 that while male beetles could be secured in considerable numbers, 

 females were apparently only caught by accident, at least they did 

 not constitute more than one per cent, of the total catch. As a 

 matter of fact the females are far less active than the males and 

 seem to be more concerned with feeding than flying about. 



The facts brought out by this investigation seem to bear out 

 very clearly the conclusions arrived at by other investigators, 

 namely, that light traps are not a practical method of controlling 

 insect pests, and that the number of noxious insects destroyed by 

 this means is infinitesimal in any case. Moreover, when we take 

 into consideration the useful insects secured at the same time we 

 are left in doubt as to whether this method does not actually do 

 more harm than good. There may be a time when certain pests, 

 at present not thought of, may be controlled by means of artificial 



