THE CODLING MOTH IN THE YAKIMA VALLEY. 5 



time of pupation. The cocooning rack (PI. I) consists of a strip of 

 soft wood 7| inches long, If inches wide, and one-fourth inch thick. 

 On one side of this a central longitudinal groove is cut one-eighth 

 inch deep and one-half inch wide. In this is glued a strip of hard 

 wood, and on each side of it is a row of transverse cells extending to 

 the edge of the rack, each cell being one-eighth inch wide and one- 

 eighth inch deep. The hardwood strip prevents the larvae from 

 boring through to the cell on the opposite side. Each row of cells 

 is covered with a strip of transparent celluloid, and a strip of paper 

 is pasted to the hardwood, on which to record the number of each 

 cell. The whole rack is covered with a thin strip of wood, held in 

 place by wire paper clips. 



Studies of the pupal period were made from the same cages as the 

 pupation studies, the date of emergence of the moth being recorded 

 daily. 



Studies of moth emergence. — Each morning, before the heat of the 

 day, moths emerging on the preceding day were counted and placed 

 in oviposition jars. 



Studies of oviposition. — Moths were confined in the regular battery- 

 jar cages, in which were fresh pear leaves and a small sponge mois- 

 tened in a solution of brown sugar. The number of moths in each 

 cage was limited to about 25, those issuing each day being confined 

 together, but separated from those issuing on other days. The 

 leaves were removed daily, the eggs counted, the sponge remoistened, 

 and fresh leaves put in the cage. No effort was made to control the 

 number of male or female moths in each cage. 



Studies of the length of life of the moths. — At the daily examination 

 of the oviposition cages all dead moths were removed and their sex 

 and length of life recorded. 



Studies of the incubation period. — Leaves on which eggs had been 

 deposited were placed between sheets of wire cloth in battery-jar 

 cages to prevent them from curling. Daily observations to deter- 

 mine the appearance of the "red ring," which is probably the germ 

 band, the u black spot," which is the black head and cervical shield of 

 the young larva, and the time of hatching were made. These obser- 

 vations were made in the evening after the heat of the day. The 

 number of eggs hatching was determined from the empty eggshells 

 rather than from the number of young larvae observed. Worm-free 

 apples were placed in the incubation cages, in order that the worms 

 might begin feeding immediately after hatching. These apples were 

 removed daily and fresh apples substituted. 



Studies of the larval feeding period. — Apples containing newly 

 hatched larvae from the incubation cages were placed in wire baskets 

 in regular cages each day. At the end of 10 days, cocooning racks 

 were placed in the cages and these examined daily, the number and 

 date of larvae leaving the fruit being recorded. This is called the 

 " stock-jar feeding method." In the bagged-fruit feeding method," 

 newly hatched larvae were placed on worm-free apples in the orchard 

 and confined by well-ventilated paper sacks for 10 days, after which 

 they were brought to the insectary and handled as in the stock-jar 

 method. 



