358 THE GYPSY MOTH. 



the number of gypsy moths in that locality the following 

 season. 



For this purpose wooden boxes, 12 by 8 by 3 inches, 

 were made, without top or bottom, these being covered with 

 brass wire gauze. A hole was bored in one end for the in- 

 troduction of the female moths, and this was closed by a 

 cork. Several different substances were used on these traps, 

 to capture the males when they flew against them, as mo- 

 lasses, raupenleim, sticky fly-paper, ejtc. Molasses proved 

 of no value, as it ran too easily, and was not sticky enough. 

 The raupenleim was not sticky enough, and soon dried on 

 the outside, so that it would not hold the males when they 

 flew against it. Sheets of sticky fly-paper, with holes 9 by 

 4 inches cut from the centre, were tacked over the gauze ; 

 these proved very efficient in securing and holding the 

 males, but it was necessary to replace them with fresh ones 

 frequently, and, to avoid this, they were painted over with a 

 preparation of castor oil and resin, which proved to be bet- 

 ter for the purpose required than the original fly-paper. 

 When a trap was first put up a sheet of fly-paper was 

 tacked on it, and each time the trap was visited the cap- 

 tured males were removed and the paper recoated so far as 

 necessary. This gum was found to keep in good condition 

 for several days, unless a large number of males were caught 

 in it, or the trap was in a very dusty place. Even when the 

 males were not caught the first time they touched the paper, 

 they were so persistent that they would immediately fly 

 against it again, and be caught in a few minutes. 



The fly-paper was removed from one trap (No. 14) after a 

 few days, and a pan of water with a little kerosene on the 

 top of it was suspended directly beneath the trap. On ac- 

 count of the rapidity with which the males fly, and the light- 

 ness with which they struck the trap, it was not expected 

 that they would be caught in the kerosene ; but, being very 

 persistent, in trying to go under the trap from one side to 

 the other they came in contact with the kerosene and were 

 destroyed. This plan was not very satisfactory, not only 

 on account of the expense, but also because the kerosene and 

 water were so frequently spilled by the wind. 



To obtain " bait" for these traps, it was found better to 



