Part VII] Beeson : Life History of Toon Borer. 
13 
PART III. 
LIFE HISTORY AND HABITS OF THE INSECT. 
Definition of terms. 
The terminology of this paper conforms as nearly as possible with 
that used in literature on moth-borers with similar habits, and in parti¬ 
cular on the codling-moth. Comparison should be made with bulletins 
of the U. S. A. Department of Agriculture. ( e.g ., Brooks and Blakeslee, 
1915, Bull. 189 ; Siegler and Simanton, 1915, Bull. 252, etc.). 
The term brood is used to designate the insect in any one of its four 
stages in any generation. Thus, a first brood larva refers to a larva 
of the first generation. 
The term generation includes all stages of the life-cycle, and is con¬ 
sidered to commence with the egg stage and terminate with the moth 
or imaginal stage. 
The life-cycle is a period extending from the deposition of the eggs 
of one generation to the emergence of the adult of that generation. 
The complete life-cycle of a generation includes the time from the 
deposition of the egg of that generation to the deposition of the egg 
of the next. 
The limits of a generation are considered to be defined by the dates 
of deposition of the first egg of that generation and the emergence of 
the last moth of that generation. 
The seasonal history of the insect comprises the several histories 
of all generations in one annual cycle. 
Number of Generations. 
The seasonal history of the toon fruit and shoot borer, Hypsipyla 
robusta, during a period of one year, normally consists of five generations. 
The succession of the generations is here summarized, but in the subse¬ 
quent tables and records, Part IV, are given details of the periods and 
limits of the stages, broods, swarming periods, etc. 
The eggs of the first generation are laid early in March when the 
toon is in flower and the first brood larvae feed on the flowers until the 
first week in April. The whole development is relatively rapid. The 
life-cycle from egg to moth is completed ordinarily in 24-29 days, and 
the whole generation is confined within a period of 8 or 9 weeks. 
The second generation possesses similarly a short life-cycle. The 
earliest individuals of the second-brood larva? emerge early in April, at 
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