15 



The total number of larv?e taken nnder the one burlap band upon 

 the above tree growing in closely cut grass ground was 1,481. We 

 did not take so large a loroportion of the larvae from any tree growing 

 upon well cultivated ground. 



WHEN THE LARV^ COME DOW^N. 



To determine what proportion of the larv?e leave the fruit during 

 the bright daylight and what proportion at night to go in search of a 

 place to spin up, I bandaged a tree that I passed each morning and 

 evening and removed the larvae at about 7.30 a. m. and 6 p. m. from 

 August 15 to 26. There were 414 larvae taken, 353, or 85 per cent, of 

 which came to the band during the night, and 61, or 15 per cent, 

 during the day, between the hours mentioned. 



DURATION OF LARVAL PERIOD. 



Dr. Riley ^ gave this jDcriod as 25 to 30 days outside the cocoon, 

 Washburn ^ as about 4 weeks. Card ^ as apparently 10 to 14 days, and 

 Slingerland* estimated the time at 20 to 30 days. In our records the 

 time has varied between 12 and 24 days, with an average of 19, at 

 Fort Collins. 



W^HERE THE LARVA ENTERS THE APPLE. 



TJnsprayed trees should be chosen to determine this point. There 

 is also danger of error if the examination of the apple is superficial, 

 as I have found that the larva often enters at the calyx, leaving no 

 castings in sight, and then burrows out at the side some distance away, 

 the latter burrow being kept open, but not the former. An examina- 

 tion of 526 apples wormj" by the first brood gave the following results: 

 Two hundred and sixt}^- seven apples were wormy at the blossom only, 

 18 at the stem only, 84 at the side only, and 157 had wormholes at the 

 blossom and also at some other place. Adding this last number to the 

 first, we have 424 out of 526 apples, or 80 per cent, with wormholes at 

 the blossom end. The apples counted were of three varieties of crabs. 



DURATION OF COCOON STAGE OF FIRST SUMMER BROOD. 



The period elapsing from the time the larva leaves the apple or 

 appears under a band to the time the moth emerges I have designated 

 as the cocoon stage. The time elapsing before changing to the chr3^s- 

 alis Riley ^ found to be 3 days. During the present summer (1901) Mr. 

 Taylor has carried through observations for me upon 76 larvae which 

 transformed to moths, for the purpose of determining theaverage time 



1 Fourth Mo. Rep., p. 22. 

 2Bul^ 25, Or. Exp. Sta.,p. 5. 

 3 Bui. 51, Nebr. Exp. Sta., p. 22. 

 4 Bui. 142, Cornell Exp. Sta., p. 23. 

 ^Fourth Mo. Rep., p. 22. 



