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LIFE HISTORY. 



Of all insocts the codling moth has the largest number of hiog- 

 raphei's. It has been studied in nearly every country in the world 

 and in all climates in which it exists. The early accounts were always 

 more or less vague and inexact and gave rise to many false ideas. 

 Gradually these points were worked out until to-day we can say that 

 the life history of the insect is as well if not better known than that 

 of any other. Yet, with all the knowledge we have of it, there remain 

 several important points to be determined ))y future work. 



It is a fundamental principle of economic entomology that in order 

 to successfully com])at an insect the life history of that insect nuist be 

 given a keen, searching study. With few exceptions these studies 

 reveal some point in the life of the insect at which it is vulnerable 

 to preventive or remedial measures. Without this knowledge efforts 

 are wasted and in some cases are a positive aid to the insects. It can 

 not be too strongly urged that each fruit grower make himself familiar 

 with the life history of the codling moth from personal observation, 

 for ))}' doing so he is placed in a position to understand the reasons for 

 measures of control and to exercise his ingenuity in applying the same 

 to his own orchard. 



The ease with which collections can be made in the larval stage and 

 the accessibility of literature pertaining to it should specially com- 

 mend this insect to teachers as a subject for nature-study lessons. 



In the present studies upon this insect particular care has been taken 

 to keep the different stages under observation in exactly the same con- 

 ditions of temperature, moisture, and light as were present in the 

 orchard in which the cages were located, and as a result the writer is 

 able to present some definite data in regard to the effect of temperature 

 upon the length of the stages of the insect under normal conditions. 



As in other lepidopterous insects, the life of the codling moth is 

 divided into four distinct stages — egg, larva, pupa, and adult. In the 

 winter and early spring the larva' may be found in their cocoons in 

 various places, as in cracks and holes in the trees. Later the larva 

 transforms into a pupa, and this in turn changes to a moth, which in 

 turn lays eggs. 



THE EGG. 



Since the time of Roesel many authors have mentioned the egg of 

 the codling moth and stated where it was laid, liut it was as late as 

 1893 that it was first accurately described and figured. In 1874 Mr. 

 W. H. Hurl but described the egg as being about one-eighth of an inch 

 in length and nearl}^ white. Kiley described it as ]>cing very small 

 and of a yellow color. Messrs. A, J, Cook, Koebele, Weir, and others 

 undoubtedly saw the eggs, but Cook in 1881 and Miss M, Walton 

 doubtless saw the ecro-s of some other insect. 



