2 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



under marked seasonal climatic variations become of particular value 

 ior comparative study, and through the duplication of certain rearing 

 experiments better averages have been established for the time of 

 occurrence and the duration of the separate stages of the insect. 



DEFINITION OF TERMS USED. 



By the use of terms which are not well defined or uniformly inter- 

 preted confusion is often likely to arise. This is particularly true 

 in regard to the terms "brood" and "generation" applied to the 

 codling moth. In conformity with previous papers on the codling 

 moth the term "brood" is here used in speaking of individuals of one 

 generation of any stage, as egg, larva, or pupa. A "generation" is 

 considered to begin with the egg stage and to terminate with the moth 

 or imago stage of the same generation, thus including all the stages 

 of a life cycle. Since the wintering larvae of the codling moth in this 

 section of the country are of both the first and the second broods, 

 which can be separated only by rearing, they are all referred to as 

 "wintering larva?" or "wintering brood of larvae." 



Similarly, the pupae and moths that result from the wintering 

 larvae and issue in the spring pertain also to the two broods. It may 

 therefore be suitable to use the terms "spring brood of pupae," and 

 "spring brood of moths" or briefly "spring pupae" and "spring 

 moths." It should be remembered that the first brood of pupae and 

 the first brood of moths are actually second to appear during the sea- 

 son. For popular purposes to avoid confusion the latter set may be 

 called "summer pupae" and "summer moths" and in sections where 

 three broods exist the second-brood pupae and moths may be termed 

 "fall pupae" and "fall moths." 



The following plan of designating the separate stages has been 

 uniformly followed by the bureau in the codling moth investigations: 

 The wintering larvse may include larvae of the first, second, and 

 third broods. 



The spring brood of pupse may include pupa 1 of the first, second, and 

 third broods. 



The spring brood of moths may include moths of the first, second, 

 and third broods. 



The first generation includes : 

 The first brood of eggs; 



The first brood of larvse, some of which winter; 

 The first brood of pupse, some of which transform the same sea- 

 son ("summer pupae") and a part the following spring 

 ("spring pupae"); 

 The first brood of moths, some of which emerge the same season 

 ("summer moths") and some the following spring ("spring 

 moths"). 



