354 Phylum Arthropoda 



made of two discs of laminated wood % inch thick and 5 inches in 

 diameter held apart by four stiff wires (B, g), and when the waxed paper 

 is placed around the wires it forms an oblong cage, 12 inches long by 3% 

 inches square. The ends, which expose the smallest surface, are covered 

 with wire screening (C, and B, w) in order to keep the moths from lay- 

 ing eggs on that part of the cage. They are also provided with a wire 

 screen cylinder (B, i) 1 inch long and 1 inch in diameter to hold a 

 feeding cotton which is kept moistened with water. When putting paper 

 on the cage a roll of waxed paper is placed on the top roller (B, d), the 

 paper is then passed over the second roller (B, e), run around the wires 

 and brought out over the lower roller (D), the loose end being held in 

 place by a clip to the wire rod (D, r). It is so arranged that the paper 

 containing the egg masses is pulled out and replaced in the same opera- 

 tion. The lower roller (D), which is hinged and removable, serves as a 

 door to the cage. When opened it gives an opening 2% inches wide, and 

 when closed against the second roller the distance between them is just 

 enough to let the egg masses on the waxed paper go through without 

 being crushed. 



The newly emerged moths are picked from the globes every day and 

 put in the oviposition cages. The operation requires a light which is 

 placed on the side opposite to the opening of the cylinder so that the 

 moths, which are positively phototropic to artificial light, are held in the 

 cylinder by the light through the waxed paper and very few fly out. 

 About 40 females and 30 males are put in each cage. If kept in the in- 

 cubator the females begin to lay 4 or 5 days after emergence and they 

 live from 10 to 12 days. The dead moths are taken out of the cage every 

 day and replaced by newly emerged ones. Since the moths are more 

 active in the dark it is necessary to cover the cage with a heavy, dark 

 paper. 



The eggs are taken out of the oviposition cages every morning and 

 left in the incubator 2 or 3 days until they are ready to hatch; then they 

 are cut from the paper and placed in 4-inch flower pot saucers with 

 food. To make a container one saucer is inverted on another and, in 

 order that they may fit closely, their edges are ground until an even 

 surface is obtained. Before being used the saucers are immersed in 

 water for 24 hours; this method has proven to be satisfactory since 

 a large quantity of water is absorbed by the pottery which supplies suffi- 

 cient moisture for the hatching of the eggs. Twenty egg masses are 

 put in each container with food and then the containers are placed in the 

 incubator. They are kept in the incubator until the larvae have reached 

 the proper stage for parasitism, which takes about 4 or 5 days. During 

 that period it is necessary to examine them daily and replace food ma- 

 terial when it begins to decay. 



