8 BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



Pupation studies. — The time of pupation of the larvae was found 

 by a daily examination of the cocooning racks. 



Studies of the pupal period. — The pupal period was determined 

 for each individual by noting the time of pupation and emergence 

 of the moth. 



Studies of moth emergence. — The records of the emergence of 

 moths were made daily. 



Studies of the oviposition, — In order to secure data on the ovipo- 

 sition of the moths, it was necessary to confine the moths issuing on 

 different days in separate cages. The foliage in these cages was re- 

 moved daily and the number of eggs recorded. 



Studies of the length of life of moths. — At the time of changing 

 the foliage in the oviposition cages, all dead moths were, removed. 

 The sex was then determined and the length of life computed. 



Studies of the incubation period. — The two distinct embryological 

 stages of the eggs previous to hatching were noted, namely, (1) the 

 " red-ring stage," or the first marked indication of the development 

 of the circulatory system, and (2) the so-called "black-spot stage," 

 or the initial appearance of the black head of the developing larva. 

 (See PL IV, B.) 



Studies of the larval feeding periods. — The feeding studies of the 

 larvae of the first brood were conducted in two ways: (1) By the 

 stock-j ar method and (2) by the bagged- fruit method. The feeding 

 periods of the larvae of the second and third broods were ascertained 

 according to the stock-j ar method only. 



In the stock- jar method, apples free from codling-moth larvae were 

 placed in a wire basket within a battery jar into which were in- 

 troduced newly-hatched larvae. These soon entered the apples and 

 completed their feeding period within the fruit. Cocooning racks 

 were placed in each jar and these were examined daily to ascertain 

 when the larvae left the fruit, and from these data the length of 

 the feeding period was computed. 



The bagged-fruit method consisted in placing newly-hatched larvae 

 on apples developing on the tree and covering the fruit with finely 

 perforated paper bags. The fruit selected was first carefully 

 examined to insure its freedom from previous infestation. The in- 

 closed fruit was allowed to remain on the tree for a period of two 

 weeks, after which it was removed and kept at the insectary under 

 conditions identical with those described for the stock-j ar method. 



THE INSECTARY. 



Most of the life-history studies of the codling moth were made 

 at the insectary, a partial interior view of which is shown in Plate 

 V. This was located to the rear of the laboratory and was partially 



