293 



In Egypt Geleckia gossypiella, Saunders, can have several 

 generations each year; some individuals, however, require 

 much longer to develop than others, and thus the number of 

 generations varies from one brood to about six. The longer 

 broods have a hibernation or aestivation period as larvae, when 

 full grown after finishing feeding and before pupation. This 

 period may last only one week, or be protracted indefinitely 

 with the larvae subjected to the same conditions. 



The pink boll-worm is attacked by the following parasites : 

 Pimpla rob orator, Chelonella sulcata, Limnerium interruptum, 

 Pediculoides ventricosus, Micros poridittm polyedricum. These 

 parasites can cause damage up to 40 per cent., or perhaps even 

 more, to hibernating larvae. The effect of the control exer- 

 cised by the parasites is already noted in the field; wherever 

 records are available the attack by Geleckia has been worst in 

 the second year, being much reduced in the third. 



The amount of damage done is very difficult to estimate. 

 In* the cotton-growing season of 1913 Gelcchia larvae did the 

 greatest amount of damage hitherto recorded for them in 

 Egypt, yet in spite of this the exportation of cotton lint 

 reached record figures. Of course the quality may have 

 deteriorated. Damage to seed is more obvious, about 10 per 

 cent, on the average having been damaged and made infertile, 

 thus reducing the germination of average seed from 85 to 75 

 per cent. From the point of view of sowing, this makes no 

 great difference, as the Egyptian cultivators invariably sow 

 from eight to twelve seeds in a hole, and later on eliminate all 

 but two of the seedlings. 



The only remedies available against this pest are the destruc- 

 tion, during the winter, of all bolls on cotton sticks stored for 

 fuel, and the fumigation or other treatment of the cotton seed 

 in the ginneries. The first of these two requirements has been 

 made the subject of proposed legislation, and it is hoped 

 that the second will be voluntarily done by the ginners, as we 

 have shown the possibility of complete destruction of all larvae 

 in cotton seed by fumigation in circulating carbon disulphide 

 vapours, or in circulating hydrocyanic acid or sulphur dioxide 

 gas, as well as by suitable treatment with hot air or by 

 immersion in weak solutions of cyllin. 



[DISCUSSION.] 



The CHAIRMAN: I think you will all wish to thank Dr. 

 Gough for his interesting paper, which illustrates very well 

 the dangers which all countries have to face so long as there 

 are no international laws for regulating the importation of 

 seeds, plants, etc. It is a question which we discussed here 

 the other day. 



