CODLING MOTH IIST COLORADO. 3 



varies from about 4,500 to 4,800 feet, Grand Junction being approxi- 

 mately 4,600 feet above sea level. 



CLIMATE. 



The climate is relatively dry, the annual rainfall being usually 

 8 to 9 inches, distributed according to the normal precipitation up 

 to and including 1916 as follows: January 0.49, February 0.64, 

 March 0.71, April 0.76, May 0.92, June 0.40, July 0.50, August 1.04, 

 September 0.95, October 0.91, November 0.55, December 0.44, or a 

 total of 8.31 inches per year. Moisture is supplied the crops by 

 means of irrigation systems, use being made of the water from the 

 Grand River. 



The day temperatures during the summer season are high, while 

 those at night are relatively low. For further details as to weather 

 conditions in the Grand Valley see Tables I and II (pp. 4 and 5), 

 which give the annual meteorological summaries of the United States 

 Weather Bureau for the years 1915 and 1916. 



EXPLANATION OF TERMS. 



In conformity with the previous life-history studies of the codling 

 moth by members of the Bureau of Entomology, certain definitions 

 of the terms employed have been adopted. 



The term " generation " is here used to include all the consecutive 

 stages of the codling moth throughout the season, starting with the 

 Qgg and ending with the adult or moth. Thus the first eggs to be 

 laid (those deposited by the first moths of the season) would start 

 the first generation ; these and the resulting larvae, pupae, and moths 

 would belong to this generation. The eggs deposited by the moths 

 which belong to the first generation start the second generation, 

 to which also belong the resulting larvae, pupae, and moths, and so on. 



The term "brood" as used in this publication is applied to any 

 stage of the codling moth which may belong to a specific generation 

 or to an unknown generation. For example, the eggs, larvae, pupae, 

 and moths which belong to the first generation are called first-brood 

 eggs, larvae, etc. 



The larvae which pass the winter include all the nontransforming 

 larvae of the first and second broods, and, in the Grand Valley of 

 Colorado, all of the larvae of the third brood. The specific generation 

 to which each of these individuals belongs can not be determined 

 unless they have been reared. The term " generation," therefore, can 

 not properly be used to include the various stages of their transforma- 

 tions ; they are simply called " wintering " or " spring-brood " larvae, 

 and the pupae and moths into which they transform are designated 

 " spring-brood " pupae and moths. 



