42 
times as much damage as the first generation, and it is necessary to 
know whether a second generation is present in order that the proper 
measures of control nmy be emplo3^ed. Great biological interest also 
attaches to this problem, as it affords an excellent opportunity for the 
study of the effects of different climates on one insect. 
The term "generation" is used instead of "brood" because it 
describes more definitely the idea intended. A generation in this con- 
nection means a number of individuals which pass through certain 
f^ages at about the same time, having begun in the same stage at the 
bv inning of anj^ given season. A succeeding generation is the aggre- 
gate of all the different broods of the individuals of the generation 
immediatel}^ preceding. A new generation is considered to begin with 
the egg stage, and continues through all the transformations of the 
insect until the moth dies. Many authors object to the term " partial 
generation," but as there is a condition in which, this term can be used 
with a definite meaning, it may be well to use it. For instance, in 
some sections of the countr}^ all the insects pass through one genera- 
tion; a few, becoming more advanced than others, ma}" succeed in 
passing through the pupal and moth stages and la}' eggs, from which 
larvae hatch and enter the fruit, whereas the majorit}" of the insects 
hibernate as larvae and do not transform until the following spring. 
As those insects which enter the fruit in the fall do not for the most 
part complete their development, at least in the field, they are termed 
a partial generation. 
In tabulating the results of observations in regard to the time of the 
various stages we find that at certain periods more individuals of a 
generation are in certain stages than at other times; and likewise we 
find periods when there are fewer insects of a certain stage than at 
other times. These periods are designated respectively the maxima 
and minima of the different generations. It is alwa3's considered that 
the larvae, pupae, and moths found in the early spring belong to the 
last generation of the preceding season and may be termed the hiber- 
nating generation. 
From the writings of European authors we find that there is but 
one generation of the codling moth in northern Europe, including 
England (Westwood) and northern and central Germany, while the 
evidence of Reaumur and Schmitberger shows that at Vienna and in 
France there are two generations. American writers have at various 
times recorded many observations of variations in the number of 
generations in the United States. Fitch seems to indicate the pres- 
ence of but one generation, while Harris says a few may transform and 
enter the fruit in the fall, though the majority of the first generation 
hibernate. Fletcher reports that careful observations extending over 
ten years convince him that near Ottawa, Canada, there is but one 
regular generation of the insect, while in the fruit-growing districts 
