50 BULLETIN 429, U. S. DEPARTMENT OF AGRICULTURE. 



Of 149 individual insects under observation, 16 were found to have 

 a total life cycle of 45 days. Two insects required 65 days and 

 represent a maximum time for the brood; two specimens were found 

 to have completed the previous stages in 39 days, which is considered 

 the minimum time. An average time of 46.91 days prevails, and a 

 range of variation of 26 days is noted. 



EGG DEPOSITION BY INDIVIDUAL MOTHS. 



Mating.— Records of egg deposition by individual females in cap- 

 tivity have proven of especial interest in connection with these 

 studies of the codling moth. Records on egg laying and mating of 

 the codling moth have been very limited, and statements by earlier 

 investigators have been largely speculative estimates. The lack of 

 information is due to the difficulty of getting moths to deposit eggs 

 in a state of captivity, especially when the individual insects are 

 isolated. Although many thousand moths have been under obser- 

 vation it has been only in rare instances that moths have been found 

 in copula. In 1913 these observations were made for the first brood 

 of moths, and in Table XLI these observations are listed under 

 numbers 21, 23, and 48. The moths in connection with observation 

 No. 21, both male and female, emerged June 22 and were found 

 mating at 10 a. m. on June 24. Eggs were deposited the same day. 

 The individuals in connection with observation No. 23, both male 

 and female, emerged June 24 and mated on June 27 at 8 a. m. Eggs 

 were deposited during the following night. The moths referred to 

 as observation No. 48, male and female, emerged July 6 and were 

 found in copula on July 7 at 9 a. m. and remained so until 2 p. m. 

 of the same day. The wings of this female were not fully expanded, 

 and this may account for the long mating, the moth when dead still 

 having the abdomen distended with eggs. Since the moths are very 

 inactive during the heat of the day it is very probable that mating 

 takes place at twilight, during warm nights, and in the morning. 

 Mating also very likely takes place under natural conditions shortly 

 after the moths take flight after emergence, and as the sexes en- 

 counter each other. 



Egg deposition. — In the course of these investigations it was noted, 

 that eggs were deposited in abundance when moths were confined 

 together in numbers in large jars. This fact led to further experi- 

 mentation and male and female moths were isolated, being 

 removed from the larger jars after two days' confinement, and 

 placed in smaller jars for observation of egg deposition. The 

 moths were first fed on diluted sugar water placed on a small piece 

 of sponge, but this method invariably made the jars sticky and in 

 consequence the moths died prematurely. Later dried pear leaves 

 were placed in each jar, each leaf being daily moistened with pure 

 water. The dried leaves, being black, showed the presence of the 

 white eggs; the most of the eggs, however, were placed on the side 

 of the glass jars. 



