TRAPPING MALES. 361 



was cut in the lower edge of the vertical boards at the 

 centre, and in this opening was secured a cylindrical wire- 

 gauze cage, three inches in diameter and height, and with a 

 convex tin top and bottom. The unfertilized females were 

 placed in this cage through a round hole in the top, which 

 was kept closed by a cork. The trap was suspended by 

 means of a hook fitting into a wire loop at the centre of the 

 top of the vertical wings. Several other kinds of traps of 

 various patterns were tried, but none proved so satisfactory 

 as the two described above ; and of these the four-leaved 

 wooden trap proved to be the best, as it allowed the females 

 to be exposed to the air on all sides, and also because it pre- 

 sented a greater area of the sticky surface. The majority of 

 the males were caught on the base boards of the traps, the 

 greater number invariably being taken on the leeward side. 

 The ' ' bait " used in all of these traps was unfertilized 

 female moths bred from pupae in confinement, though the 

 pupae themselves, and dead and fertilized females, were also 

 tried for the purpose of ascertaining whether they would 

 attract the males. It was found advantageous, when keep- 

 ing pupae in confinement, to moisten them with a fine spray 

 of water from time to time, to keep them from drying up so 

 much as to prevent them from emerging. The "bait" in 

 the traps was renewed as often as necessary. The best 

 means of carrying the newly emerged females was found to 

 be a cloth-lined box, as they would cling to the lining, and 

 could be transported in this way with little or no injury. 

 The traps were painted over with a sticky gum composed of 

 sixty per cent, of crude resin and forty per cent, of crude 

 castor oil. The resin and oil were melted together, and 

 applied, while warm, to the traps by means of a flat varnish 

 brush, care being taken not to put the gum on the gauze. 

 Most of the traps required repainting about every second 

 day, though some required it oftener. A small pointed 

 trowel was used in removing the . captured males from the 

 glue, and a pole with a small hook at the end was used in 

 removing and replacing the traps in the trees. The trapping 

 operations were closed August 13, for lack of " bait," and 

 also because so few males were then captured that it did not 

 seem wise to continue the work. 



