292 



DR. L. H. GOUGH. 



we have just been discussing was ginned in the laboratory, special precautions 

 being taken to retain every single one, whatever its size or condition. 



Part of the fluctuations shown in Table II appears to be the same for all samples 

 taken in any one year as contrasted with any other year, and is probably annual. 

 due to climatic variations. 



The reduction of the average weight of sound seeds derived from attacked bolls 

 is not due to a general reduction in weight of all the individual seeds in the sample, 

 but to an increase in the percentage of the smaller weight seeds at the cost of the 

 heavier grades. This is fairly evident from Table VIII, hi which a number of samples 

 are recorded that have been weighed out seed by seed. 



It is thus obvious that in some manner Gelechia causes some of the sound seeds 

 developing in attacked bolls to lose weight. 



Table IX has been prepared to show the same facts, but from a different point of 

 view. It is compiled from the results of the examination of 31 bolls ; in this 

 case every sound seed (352 in all) has been weighed separately. Of the 139 seeds 



Table IX. Gelechia Attack and Abnormal Seed Weight. 









Percentage of sound seeds 



Number of 



Number 



Total 



whose weight compared to 



attacked seeds 



of bolls 



number of 



the heaviest seed of the 



per boll. 



examined. 



sound seeds. 



same boll is less than 









f 1 I 



i 







10 



139 



6 



3 



o 



1 



3 



36 



22 



19 



6 



2 



4 



49 



12 



6 



4 



3 



3 



35 















4 



4 



39 



5 



3 







5 



1 



8 



38 



13 



13 



6 



3 



29 



7 



7 



7 



7 



1 



8 















8 



1 







17 











10 



1 



3* 



100 



100 - 



C7 



Actual Numbers. 



Totals Sound Bolls 

 Attacked Bolls 

 Average per 10 Bolls 

 Sound Bolls 

 Attacked Bolls 



10 

 21 



139 

 213 



139 



101 



s 



25 



12 



4 

 17 



4 

 8 



Expressed as percentage of abnormally small to total sound seeds. 



100 

 100 



6 

 12 



Standard deviation calculated from the 139 seeds from 10 sound bolls only, the heaviest 

 seed in each boll being calculated as 100= IS. Probable Error Mean = 0-936. 



* All 3 seeds have been considered as undersized ; the heaviest oniy weighed 29 mg. 

 Damage being obvious, comparison was made with the boll whose heaviest seed was 

 lightest. 



