318 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



The Net Trap. — A net trap of my own invention, and which I con- 

 sider the best of this class, deserves the following consideration : Ob- 

 Observing how moths attracted by light approach panes of illuminated 

 glass, descending or ascending thereon, that most of the moths allured 

 by light do not plunge into the blaze, but pass near it by a more or less 

 circuitous course, often describing ellipsoid figures and returning to re- 

 peat the same, so that such moths are not caught by the common lamp- 

 traps which have more or less cylindrical or cubic form, with the several 

 horizontal diameters not extremely unequal, I planned a screen, made 

 preferably of glass or glass and sheet metal in combination with a light, 

 or bait, and other arrangements for taking moths and other insects, as 

 represented in Plate LXI, Fig. 1. The two ends of the apparatus are 

 alike. Observing one end with reference to the lettering, s is a stake 

 having a slit sawtd down into its top, on its side a cleat, c, and above 

 this two opposite notches, x. In the slot is supported one end, i, of a 

 large plate of glass, t, the larger the better. It had better be 3 feet 

 square or more. A sheet of metal, v r, is bent to have two slight slopes 

 like a roof, and is placed with its angle fitting upon the top edge of 

 the glass. This angle may be bent up into a narrow fold, v, which will 

 pinch firmly upon the glass. The roof may be very narrow, and good 

 results are obtained when it is entirely omitted. Its outer margin 

 should bend suddenly downward. The stake should straddle the glass 

 to near the top thereof. The lateral halves of the stake thus form wings 

 or flanges projecting at right angles from the glass. These may be 

 made wider or with an edge projecting toward the light from the outer 

 margins of each. Such a recurved flange is easily formed by tacking 

 a strip of sheet metal upon the side of the stake. The projecting parts 

 of the sides and the roof have a specific function, since the lantern is 

 placed opposite a lower corner of the glass and the insects, attracted by 

 it or by bait placed below, approach by a more or less circuitous course 

 to strike against the glass. If the insect strike with but little force it 

 flutters on the glass while sliding downward to fall into the other catch- 

 ing-devices below. But when the insect strikes the ]date swiftly or at 

 an angle it will be deflected oft". The insect is observed habitually to 

 move upward or horizontally as a rale on nearing the light and the 

 plate, hence if it fly or glance suddenly off horizontally, the lateral 

 wings catch it, or if it dart upward it strikes the roof, so that in either 

 case it is precix)itated downward into the devices beneath. The lower 

 edge of the glass forms a septum through the long, wide, slot-shaped 

 opening of the bottom of a trough-shaped hopper, jj, which has flaring 

 sides so that moths descending from either side of the j^ane shall fall 

 through it. The end of this hopper is supported upon the stake in 

 notches, x, or otherwise. A large net, n m, of foundation lace or other 

 fine netting has its mouth attached to the upper margins of the trough, 

 wlllch forms a narrowing entrance passage, projecting into the net. 

 The top of the net is preferably held wide and upward, at n n^ so that 



