PROCEEDIXGS OF THE THIRD EXTOMOLOGICAI. MEETING ill 



separate the first from the second picking. This is confirmed by 

 breeding results. The emergence from green bolls collected between 

 1st September and 10th October 1917 gave 5 per cent., from 11th October 

 to end of November 23 per cent, long cycle moth's. The resting period 

 can last up to two and a half years. 



Unfortunately it is not possible to make direct observations, by 

 taking out and isolating larvae, as they appear to react immediately 

 to the stimulus of the interference, and thence-forward to behave in 

 a manner wliich would not be the normal one if no interference had 

 taken place. 



As already stated, it is not safe to base any conclu.sions on 

 the beha^^our of larvse put into unnatural surroundings. In our work 

 we have always recognized tliis as a fact, and in our endeavours to obtain 

 information have frequently had recourse to indirect methods, utiUzing 

 statistics based on sufficiently large masses of figures. Thus the 

 problem, does the resting stage larva feed, has been tackled by the 

 weighing of hundreds of larvse at intervals during several months. 

 Needless to say the larvse were extracted from the seeds they inhabited 

 immediately before weighing, and the same indixiduals were never 

 used twice. They were weighed -in groups of one hundred together, 

 several groups being handled each time. 



The result obtained shows that during the period from February to 

 June there is a continuous and significant fall in weight (see 

 Plate 81). This does not necessarily prove that the larvse were • 

 fasting, but it certainly shows that they were not actually making 

 good their losses in substance. 



It is mainly the resting stage larvse which (in Egypt) serve to carry 

 the species over from one year to the other. They are found almost 

 exclusively in seed, whether in seed cotton, ginned seed or in abandoned 

 bolls in the field. 



The resting stage is the only period of the life-cycle of the Pink 

 Bollworm during which it can be controlled, and, acting on the advice 

 of the Entomological Section of the Ministry of Agriculture, the Egyptian 

 legi.slator has seized the opportunity given by the insects to ensure 

 its destruction, (a) in the cotton field by ordering the pulhng up of the 

 cotton sticks and the destruction of the remaining bolls after the last 

 picking, and consequently ensuring the destruction of the larvse left 

 in the field. (6) by the treatment by heat or fumigation of the seed in 

 the ginneries, and (c) by compulsory screening of all stores where seed 

 cotton or cotton-seed is kept during the period from May to August. 



Larvse inhabiting green bolls almost invariably leave the bolls before 

 pupating. During the examination of three-c[uarters of a million bolls 



