That there is i^rol^able error in some of the announcements as to the 

 number of broods of this insect is further evidenced in the fact that 

 I have received opinions of entomologists of equally good standing in 

 which they estimate the number of life cycles diiferently by two broods 

 in the same locality. Both can not be correct. 



Again, if the codling moth is partial-brooded in a locality, it seems 

 improbable that we should find it uniformly i^assing the ^vinter in the 

 larval state, yet all authorities seem to agree that such is the case. 



HOT^' TO DETERMINE THE XUMBER OF BROODS. 



It is not a simple problem to determine the number of broods of the 

 codling moth where there are more than one. As the insect always 

 winters as a larva, it must be double brooded, at least, if all the larvae 

 of the first brood of Avorms feeding in the fruit change to the pupa 

 state soon after leaving the apples. Care should be taken to obtain 

 first-brood larv*, however, and if they do not change in breeding 

 cages, bands should be left upon the trees for two weeks at least, and 

 then the cocoons opened to see if any contain pux:>?e. If a good num- 

 ber of larv?e are obtained and none transform under natural condi- 

 tions, it is fair to conclude that the insect is single brooded in that 

 place. According to my experience the first-brood larv?e Avill con- 

 tinue to ai^pear for fully one month before those of the second brood 

 will begin to arrive. 



The time occupied by the codling moth in passing through its com- 

 plete round of development during the summer will average about 

 seven weeks. Then if we know when the first larvae appear in the 

 spring and when the latest ones cease to appear in the fall in a given 

 locality, it will be a very simple mathematical comj^utation to deter- 

 mine a theoretical number of broods for the season, but it will be no 

 evidence whatever that such a number exists, unless we know that all 

 the eggs of a brood are deposited at one time and that all the indi- 

 viduals of the brood run their course at the same rate. We know 

 these conditions never occur in case of the codling moth. The in^ob- 

 lem we have to solve is one in which many runners are to cover a cir- 

 cular course one or more times; they run at widely varying si^eeds, 

 and some of the earliest to start will go around once before the late 

 individuals make their start. AVe sui)i:)ose all are to cover tlie course 

 the same number of times, and we are to find that number and also 

 learn whether the number is the same for all. Then what must we 

 know in order to determine our unknown quantities? We must know 

 tlie beginning and the end of the period during which the insect starts 

 upon its various rounds of development, and we must know the range 

 of time in comi:)leting that cycle; then we must know whether those 

 that complete one circuit start upon the next. If one starts upon the 

 course, it goes completely around — at least we know no exceptions to 



