2 - 



Thus it was found that in a first picking sample only eighty seeds per 

 thousand had been damaged by the seed worm as against 377 seeds 

 per thousand damaged by this insect in a second picking sample, 

 showing an increase of 207 per thousand in damaged seed during the 

 interval of approximately six weeks that separates the first and second 

 pickings. 



The extent of the increase in numbers at this period is, however, 

 not so interesting from the point of view of pest control, as is the 

 fact that during the harvest season (i.e. the period including the first 

 and second pickings) the life-cycle of Gelechia becomes modified, and 

 that it is soon after the first picking that the full fed seed worm inter- 

 calates a period of hibernation as larva before pupating. 



Examining first picking seed in January a certain number of 

 Gelechia larvae are found hibernating, together with a number of dead 

 worms. These hibernating larvae were not necessarily full grown at 

 the time of picking, or of ginning; safely hidden in the " double" 

 seeds they can have finished feeding after both of these operations 

 were completed. In the case of the dead worms there is of course 

 nothing to show when or how they died. Taking the number of 

 living hibernating worms, found in January in first picking seed 

 and comparing them with the number of damaged seeds, six living 

 and thirteen dead worms were found to eighty damaged seeds, or 

 seventy-five living worms in one thousand damaged seeds. 



For second picking seed the' numbers of hibernating worms 

 present in January are much greater. The sample we examined 

 contained 377 damaged seeds in every thousand seeds. In this case 

 118 living and fifty-six dead worms were found in the 377 damaged 

 seeds, or 313 living worms in every thousand damaged seeds. 



The proportion of living worms found in January in one thousand 

 seeds (uninjured and damaged) in the sample examined consequently 

 works out at six per thousand in the case of the first picking and 118 

 per thousand in the case of the second picking. 



The question immediately arises, what has happened to reduce 

 the proportion of living worms to damaged seeds so considerably 

 in the first picking seed as compared to the second picking seed. 



A solution to this problem is offered by the observation that 

 very large quantities of larvae leave the seed and pupate on the sacks, 

 especially in first picking seed. The moths from these pupae emerge 



