404 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



into the oil. The catcher is illustrated in Figure S. The runners, which 

 straddled the hills, were made of 2 by 12 inch rough pine. They were 6 

 feet apart and about 8 feet long. The size of the machine should be made 

 large enough to cover the growth of the plants, until all danger of attack 

 is past. The top and sides were light wooden frames, entirely covered 

 with roofing paper. The back frame was covered with screen wire. 

 Directly under this was an oil trough m.ade by cutting o-gallon oil cans 

 in half longitudinally and fitting them closely together end to end. This 

 m.ade a cheap trough and the cross divisions prevented splashing. 

 Canvas curtains were hung between the runners, both in front and at 

 the back, to shut out entirely all the light, except that which came 

 through the screen . These curtains were made of strips of canvas about a 

 foot wide, which overlapped, so that they would easily pass over the 

 plants, and close as quickly as possible afterward, keeping out the light. 

 Before these curtains w^ere used many beetles escaped under the ends of 

 the m.achine. The "tickler" was a rod extending through the back screen 

 with light weights on strings at the inside end. The rod fitted loosely in 

 a hole through a cleat across the middle of the screen, so that it could 

 be moved freely from, side to side, up and down, and also in and out, and 

 the beetles in all parts of the plants could be disturbed. 



In practice the catcher was drawn by two horses and operated by one 

 m.an. The machine was stopped over each hill and the beetles stirred up. 

 When first disturbed, a large proportion of the beetles dropped to the 

 ground, then immediately crawled up on some projection and flew 

 toward the light where they hit the screen and fell into the oil trough^ 

 The longer the machine stayed over a hill, the larger the catch, but it was 

 determined that all things considered, a pause of about 30 seconds was 

 best. With a stop of this length, 75 to 80 per cent of the beetles were 

 captured, and the work could be conducted at an average rate of 100 

 hills per hour. 



This m.achine was used for two successive seasons and proved very 

 satisfactory. In 1918 a sm.all m.achine about 2]A. feet square was made. 

 This was set by hand over small summer squash plants. It worked well 

 and proved entirely satisfactory while the plants were small enough to 

 be covered by it. 



^These movements of the beetles were definitely demonstrated as one of the auth- 

 ors spent almost an entire day inside the machine, observing their actions under var- 

 ious conditions. 



