CODLING MOTH IX COLORADO. 9 



shaded by trees, vines, awnings, and other buildings. As will be 

 noted in the photograph, the insectary was of open-type construc- 

 tion, permitting free circulation of the air; it was 40 feet long 

 and 11 feet wide, with the lowest part of the roof 11 feet in elevation. 

 The temperature conditions within the insectary closely paralleled 

 those in the orchards, as was determined by frequent observations. 

 A thermograph and maximum and minimum thermometers were 

 kept in the insectary for temperature records; and the average daily 

 temperatures used in the various graphs and charts throughout this 

 publication were computed for each day by adding the temperature 

 recorded by this thermograph for each hour of that day and divid- 

 ing the sum by 24. Other data pertaining to weather conditions 

 were obtained through the courtesy of the local station of the United 

 States Weather Bureau, which was located within a half mile of 

 the insectary. 



SEASONAL-HISTORY STUDIES OF 1915. 



The seasonal-history studies of the codling moth were commenced 

 in 1915 with the observations of the time of pupation of the spring- 

 brood larva?. 1 The climate throughout the season was generally nor- 

 mal, except in early May, when subnormal temperatures which fell 

 below the freezing point occurred successively on the mornings of 

 May 1 to 4 inclusive and again on May 7. On the 2d of May the tem- 

 perature dropped to 22° or 23° F. in many sections of the valley, one 

 exception being the Palisade peach district, which is usually favored 

 with higher minimum temperatures. At the time of the freezes most 

 apples had just dropped their blossoms, except the late-blooming 

 varieties, as Rome Beauty and Jeniton. 



As a result of the low temperatures, the apple crop in the Grand 

 Valley, with the exception of that included in the Palisade district 

 and in a few orchards where oil heaters were employed, was prac- 

 tically destroyed. Here and there were to be found a few pears, the 

 blossoms of which seemingly were not so readily destroyed by the 

 freezes as were those of the apple. The general shortage of the apple 

 crop, however, did not in any way interfere with the life-history 

 studies, since sufficient fruit was at hand for feeding and other 

 purposes. 



In referring to the tables the reader should bear in mind that each 

 table is a unit in itself. Successive tables are not necessarily con- 

 tinuations of the life history of all of the individuals given in the 

 previous table. For example, it will be noted that Table III is the 

 record of the time of pupation of 320 wintering larvae and that Table 

 IV includes observations on the length of the pupal stage of only 

 233 of these individuals. Differences of this character may be due to 



1 These larvae were collected from banded apple trees in the fall of 1914 by Mr. R. J. 

 Fiske, of the Bureau of Entomology. 



