raocEEDiNGs or the third entomological meeting 543^ 



to the traps. From a practical point of view 24 traps -per feddan are 

 I think out of the question — unless they gave immunity from Pink 

 Boll worm attack. 



"It is a pity that this experiment was so interfered with by the 

 flooding and the lack of uniformity in the crop apart from the question 

 of insect pests. I should say that roughly one-third of the 12-lamp 

 plot gave practically no cotton owing to poor soil and to the influence 

 of a row of mulberry trees along one side. As regards growth the 

 6-lamp and the control plots were most alike, but in each the growth 

 of the plants was rather irregular. 



" I wonder why trapping moths does not have more effect, and 

 suppose it is because one does not catch a large enough proportion of 

 the total moth population present. It is a difficult matter to explain 

 why one can catch some individuals and not others. Can the members 

 of a species vary individually as regards their reaction to a light stimulus? 

 Sometimes I begin to think that perhaps it is only the foolish or inquisi- 

 tive moths which are lured away from their proper occupations to 

 destruction in the traps ! 



" One point that was rather striking was the number of injured 

 bolls on plants immediately surrounding and actually touching the 

 traps — in this respect there seemed to be no difference in close and 

 remote plants as regards distance from a lamp. 



" Some years ago I tried the effect of coloured lights. Blue lanterns 

 appeared to attract Earias insulana to a greater extent than white, but 

 I rather think that the position of the blue in relation to the white against 

 which it is being opposed may have a good deal to do with the matter. 

 The Pink Bollworm moth did not appear to exhibit any partiality for 

 blue. 



"As to the relative attractiveness of coloured Hghts — (if there is 

 any such thing — because it may be entirely a question of brilliance, 

 visibility, etc.) — the figures I obtained placed the coloured light traps 

 in the following order. 



1 2 3 



Blue. White. Green. Red. Oraiigt.. 



" The question of high-power against low-power lights is of interest 

 because possibly one very brilliant incandescent oil gas light might 

 do the work, say, of 24 low-power paraffin lamps. I was only able to 

 carry out a trial of this nature on two occasions. The results obtained 

 showed that although the bright light (500-1000 candle power) caught the 

 most moths it only reduced the catches in the paraffin lamp traps close 

 to or just beneath it. 



VOL. II I 



