April, '15] 



ENTOMOLOGISTS' PROCEEDINGS 



241 



With these points in mind a trap was devised in 1914 to run on 

 light wheels (PI. 10, fig. 3) in order to reduce the labor to a min- 

 imum. A pair of light springs should be fastened to the front of the 

 box (PI. 10, fig. 2, D, D) to prevent it from dipping into the soil, 

 since otherwise a portion of the tanglefoot soon becomes covered with 

 dust. This arrangement works nicely on even ground; but carrying 

 the trap will probably be found to be more efficient. A count of the 

 number of beetles caught b}^ this trap showed 1,357 as a result of 

 covering one-twentieth acre, which is at the rate of over 25,000 per 

 acre.^ 



The expense involved in the use of such a trap should be moderate. 

 A simple trap can be made by anyone in a few minutes. It is largely 

 a matter of adapting the box to the size of the plants to be treated. 

 When the sticky surface becomes matted over it may be renewed 

 a time or two by scratching it with a wire comb or brush. Warming 

 the tanglefoot made it easier to apph^ a thin even coat. 



The ordinar}^ routine spraying of potatoes will control the flea- 

 beetles to some extent. However, from these preliminary experi- 

 ments the apparatus described is believed to have a place in cases of 

 severe infestation; and in caring for small areas of various garden 

 crops which are attacked by one or another species of flea-beetle. 



Mr. T. J. Headlee: I would like to know whether these experi- 

 ments have been tried on a large scale throughout the season for the 

 purpose of determining whether potatoes can be protected in this way? 



Mr. C. L. Metcalf: We had in mind to do this but the infestation 

 of flea-beetles in North Carohna was 250 miles from our headquarters, 

 and we found it absolutely impossible to use this trap at frequent 

 intervals throughout the season. I am therefore unable to say but 

 I see no reason why it might not. 



Vice-President Glenn W. Herrick: How often did the trap 

 have to be coated inside? 



Mr. C. L. Metcalf: That would vary greatly with conditions. 

 We could cover as much as half an acre or an acre and then by scratch- 

 ing the surface slightly go on for a quarter of an acre farther perhaps. 

 It would need to be removed altogether from five to perhaps ten or 

 a dozen times in the course of a day. 



President H. T. Fernald: If there is no further discussion, we 

 will now adjourn. 



Session adjourned at 5.30 p. m. 



^Incidentally a species of leaf-hopper (Empoasca mali) was taken at the rate of 

 about 40,000 per acre. 



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