27 



egg'S. The writer was unable to secure eggs in this way. In onlj^ 

 two instances has the writer made detinite oliservations on the number 

 of eggs laid by a single female moth. Two pairs of moths were 

 secured in copula and placed in separate limb cages. In one cage 21 

 eggs were found, but as the moth escaped the observation was incon- 

 clusive. In the other cage 25 eggs were laid, but a spider put an end 

 to the experiment before a detinite conclusion was reached. In view 

 of these incomplete observations the writer can onl}' venture an 

 opinion that the maximum number of eggs laid by one moth is about 

 50, with the average between 30 and 40, which is comparable to defi- 

 nite records of other insects of this family. 



THE EGG-LAYING PERIOD. 



Upon dissection of the ovaries of the female of the codling moth 

 the eggs are found in various stages of development. It is also noted 

 that eggs are laid when they are in different stages of maturity. 

 From these facts we may conclude that the egg-la3'ing period extends 

 over some time. Various authors have given the length of time from 

 the emergence of the moth to the beginning of the laying of the eggs 

 as from 48 hours to (> or 8 days. Professor Gillette gives the time as 

 about 5 days. The various records of writers show that this time 

 varies from 2 to 7 days, with an average of from 4 to 5 days. 



DURATION OF EGG STAGE. 



In 1746 Roesel stated that the ogg hatched in 8 days. Recent authors 

 give the length of the stage as follows: LeBaron, one week; Wash- 

 ))urn, 5 to 10 daj's; Riley, 4 to 10 days; Slingerland, one week; Card, 

 8 to 10 days; and Professor Gillette, 6 to 8 days in his laboratoiy, 

 with a known temperature, and in the orchard one day longer. Cooley 

 records 12 da3"s as the length of the stage of one egg. 



The results of observations upon 164 eggs and observations of Pro- 

 fessor Cordley are given in Ta))le I, with the total and average efi'ect- 

 ive temperature to which tlie eggs were subjected. 



Table I. — T)itr<dUni of cgf/ ^tagc of codling moth. 



Number 

 laid. 



1902. 

 May m 



Aug. 11 



Aug. 12 



Aug. 16 



Aug. 26 



Date 

 hatched. 



1902. 

 June 11 

 June 12 

 June 13 



Aug. 21 

 Aug. 23 

 Aug. 25 

 Sept. .5 

 Sept. 6 



Number 

 hatched. 



Period of 

 incuba- 

 tion. 



Days. 



Total ef- 

 fective 

 tempera- 

 ture. 



o p 

 228 

 253 

 347 



206 

 266 

 217 

 247 

 276 



Average 

 effective 

 tempera- 

 ture. 



' F. 

 19 

 19 



24.7 



