390 COTTON 



on the developing lint, and by their presence damage 

 and stain the lint in the section of the boll they have 

 attacked, Gelechia larvae feed on the seeds only, hollow- 

 ing them out and living in the cavity they make. This 

 causes twofold damage. The lint developing on an 

 injured seed does not develop normally, the extent of the 

 damage depending on the developmental stage of the 

 seed when first attacked. The lint may consequently 

 hardly develop at all, remain shorter and weaker than 

 normal, or be scarcely affected. The injured seeds 

 naturally lose their germinating power and value for 

 crushing. The lint is not, however, stained by the larvae 

 nor blackened by sooty mould, as happens frequently 

 after an attack by Earias. 



During the course of its development each Gelechia 

 larva may attack more than one seed; at the time of 

 maturity of the bolls it is normal to find " double " seeds; 

 the larvae, after having more or less completely hollowed 

 out a seed, attaches a second seed to the opening of the 

 first by a web of silk threads, and feeds on the contents 

 of the second seed. A third seed is sometimes attacked 

 and stuck to the first two in the same way. Such double 

 seeds are readily found in unginned cotton by passing the 

 lint between the fingers and feeling for the seeds. That 

 they are very firmly spun together can be seen by the 

 fact that the double seeds mostly pass intact through the 

 gins, with the enclosed larvae unhurt. 



We have invariably found Gelechia pupating inside the 

 double seeds, except where this has been experimentally 

 prevented, though, according to Mr. Andres, the larvae 

 leave the seeds to pupate elsewhere. When removed 

 from the interior of the seed, full-grown larvae spin new 

 cocoons for themselves, the period required for them to 

 start spinning evidently depending, as already stated, to 

 a great extent on temperature. 



Some larvae which had been removed from their 

 original double seeds in making their cocoons employed 

 nothing but their own silk, economizing the silk by 

 leaving the glass of the tubes in which they were confined 

 to form part of the walls of the cocoon. Others, how- 

 ever, utilized foreign bodies to strengthen or to help out 



