@ ARTICLE VII.—Codling-moth Investigations of the State Entomolo- 
gist’s Office, 1915, 1916, and 1917. By P. A. Gienn, Chief Inspector of 
the Division of Plant Industry, State Department of Agriculture. 
INTRODUCTORY STATEMENT 
To secure accurate data in regard to the life history and the seasonal 
history of the codling-moth in Illinois, and the relation of climatic condi- 
tions to the rate of development and the time of appearance of the various 
_ stages of the insect, an investigation was begun in the spring of 1915 
under the direction of Doctor S. A. Forbes, then State Entomologist. 
_ The principal station was established at Olney in charge of the writer, at 
that time and during the whole period of this investigation on the staff 
of the Entomologist.* Other stations were at Ozark, about 80 miles south 
and 45 miles east of Olney, in charge of Mr. L. M. Smith; and at Plain- 
view, 40 miles north and 100 miles west of Olney, and at Springfield, 70 
_ miles north and 90 miles west of Olney, in charge of Mr. W. P. Flint. 
. The station at Olney was equipped with large, screen-wire cages 
- covering entire trees, a field laboratory and all necessary small cages for 
_ the observation of individual insects in all their stages, a self-recording 
_ thermograph, a self-recording hygrograph, a Livingston porous cup 
_ atmometer for measuring evaporation and a rain gage (Fig. 8, p. 230), 
_ standard maximum and minimum thermometers, and a sling psychrometer 
_ for checking daily the records of the self-récording instruments. The 
_ other stations were provided with instruments for keeping a record of 
_ climatic conditions. 
At Olney a continuous daily record was kept of the history of all the 
_ stages of the insect. At the other stations band records and other data 
_ were recorded such as would enable us to follow the main features of 
| __ the seasonal history of the insect. 
DEFINITION OF TERMS 
4 To avoid confusion resulting from a misunderstanding of terms, 
_ the following definitions are given: 
: The term “stages of the codling-moth” refers to the four distinct 
a Be in the life of the insect: the egg, the larva, the pupa, and the 
adult. 
a * As a consequence of the passage of the Civil Administrative Code in 1917, the writer 
_ .was transferred to the State Department of Agriculture, and the major part of this report 
has been written since he became a member of this department, the State Entomologist's 
office having been by the same law merged in the Natural History Survey of the State, with 
Dr. Forbes as its chief. This double relation has not, however, affected the character of 
this report, which has been prepared under the supervision of Dr. Forbes, and with a view 
to its publication as a survey bulletin. 
a 
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