THE CODLING MOTH IN MICHIGAN. 



13 



111 Table IX are given the results from 17 separate "stock-jar" 

 experiments, so called because of the nature of these experiments. 

 Medium-sized glass jars of about 1 gallon capacity were found to be 

 well suited for the purpose. To provide for a certain amount of 

 moisture a layer of damp sand was put in each jar; food was fur- 

 nished the moths in the form of diluted sugar and honey solution 

 placed on a small piece of sponge. In each cage a certain number of 

 moths, of known date of emergence, was confined, and throughout 

 the course of the experiments a daily record was kept of egg deposi- 

 tion and the length of life of the moths. The eggs were laid indis- 

 criminately all over the cage, on the sand, on the sides of the glass, 

 on apple foliage and fruit, and on the cloth cover of the jars. 

 When too many moths were confined together eggs were even placed 

 on the wings and backs of some of the moths. For the purpose of 

 recording the egg stage it was found desirable to have the moths 

 oviposit on pear leaves in place of fruit because the leaves darken 

 upon withering, so that the light-colored semitransparent eggs may 

 be better observed. Each day fresh foliage was placed in the cages, 

 which insured eggs of a given date of deposition. 



On an average the moths commenced to oviposit three days after 

 the date of emergence and most of the eggs were laid within a 

 week of emergence. In a few extreme cases eggs were laid the 

 second day after emergence. In one instance the last eggs were 

 laid 15 days after the date of emergence. (See Table IX.) Several 

 moths in the stock jars survived from 19 to 25 days. 



Length of life of moths. — A summary of observations on the life of 

 529 moths is given in Tables X and XI. The average length of life 

 was 9.44 days, the maximum 25 days, and the minimum 2 days. 

 These moths were from the stock-jar experiments previously de- 

 scribed. 



Table X. — Summary of observations on the length of life of 529 moths of the spring 

 brood in confinement, Douglas, Mich., 1910. 



Table XI. — Summary of Table X. Length of life of moths of the spring brood, 1910. 



