CODLING MOTH IN NORTHWESTERN PENNSYLVANIA. 81 



TIRST-BROOD LARVAE. 



As has been already stated, some of the first-brood larvae do not 

 transform with the rest of the brood, but spin up for the winter, hiber- 

 nating along with second-brood larvae. In the rearing of the codling 

 moth separate observations were made for the two sets of larvae, 

 which are here treated separately as " transforming" and " wintering" 

 larvae. 



Time of hatching. — In the rearing cages the first larvae hatched 

 June 30, but these were not from eggs of the earliest moths, as the 

 latter failed to oviposit in captivity. Considering, however, the 

 emergence and oviposition records of the moths, previously described, 

 it is very probable that eggs occurred in the field on June 23 and 

 continued to appear until the end of July. In the rearing cages the 

 last larvae of the brood hatched June 22, while in the field two newly 

 hatched larvae were found in apples as late as July 25. 



Number of larvse, developing in each apple. — In the rearing of the 

 codling moth great numbers of young larvae entered the same apple, 

 but when the apples were examined at the time of maturity of the 

 larvae only one or, rarely, two or three larvae were found in the 

 same fruit. In orchards usually only a single larva is found in each 

 apple, although the apples may show several empty eggshells and 

 entrance places of the young larvae. The writer observed, on July 

 2, 1909, in the course of rearing the grape-berry moth (Polychrosis 

 viteana Clemens), how a newly hatched larva devoured another of 

 its own kind, both having emerged at about the same time. It is 

 very probable that where larvae of the codling moth occur in num- 

 bers many of them meet a similar fate. 



Period of feeding of transforming larvse. — In Table XXII are given 

 the feeding periods of 53 individual larvae which were reared in 

 cages. On an average the larvae remained in the fruit 26 days, a 

 single larva remained 37 days, while the shortest period in the fruit 

 was 17 days. (See Table XXIII.) 



Period of feeding of wintering larvse of the first brood. — On an aver- 

 age the wintering larvae of the first brood remained 31 days in the 

 fruit, while the transforming larvae remained only 26 days. (See 

 Table XVI.) Records of the feeding period for about 200 winter- 

 ing larvae were taken from observations in rearing cages, as shown 

 in Table XIV. 



