84 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



remained 20 months in the larval stage without taking food or water 

 and that the other specimen remained 23 months in the cocoon as 

 larva and pupa. The two larvae had made their cocoons in a large 

 glass vial. They came under the writer's observation in 1910. 



The ability of an insect to remain dormant for a whole season and 

 to transform subsequently the third season may possibly occur more 

 frequently than has been actually observed. Such an adaptation 

 would be of particular advantage to the species in surviving adverse 

 seasons. 



CODLING MOTH LARV.E FEEDING ON APPLE FOLIAGE. 



To test the feeding habits of the codling moth larvae on apple 

 foliage three branches from which the fruit had been removed were 

 bagged and on each 10 newly hatched larvae were placed June 10. 

 When examined July 20 it was found that in all three bags feeding 

 had taken place, and particularly had the tender growths at the tips 

 of the branches been eaten. In one of the bags, at the place where the 

 same had been tied around the branch, one half-grown dead codling- 

 moth larva was found in a cocoon. In one of the other bags one dead 

 pupa was found, which was hardly two-thirds the average size. In 

 the third bag no insect was found, though there was evidence of feed- 

 ing. It may thus be suspected that in cases of total crop failures the 

 insect can subsist on foliage in sufficient numbers for the perpetuation 

 of the species. 



SUMMARY. 



The present account of the life history of the codling moth in 

 Michigan is based upon a series of studies made in 1909, 1910, and 

 1911. 



In the course of a year the codling moth in Michigan produces one 

 full brood and a partial second. 



In the field the earliest moths of the spring brood commence to 

 appear from 5 to 10 days after the apple blossoms drop, and the ear- 

 liest larvae of the first brood hatch from 3 to 4 weeks after the petals 

 drop. The earliest larvae of the second brood hatch from 10 to 11 

 weeks after the petals drop. During exceptionally warm and for- 

 ward seasons the second-brood larvae may appear considerably 

 earlier, and were, in 1911, observed 8 weeks after the petals dropped. 

 This record, however, should be considered very exceptional. 



The time of appearance and the periods of occurrence of the differ- 

 ent stages of the codling moth are shown in figure 11, which, with the 

 exception of the spring pupal stage, closely represents the seasonal 

 progress under average conditions. Figure 20 similarly shows this 

 progress in the development of the insect under prevailing warm and 

 exceptionally forward seasonal conditions. 



