384 



that liermetical sealing will probably prove to be effective on a large 

 scale as a remedy for badly weeviled grain, as well as a preventive 

 measure. 



This has subsequently been confirmed [see this Review, Ser. A, 

 vii, p. 94]. The carbon dioxide given of! by the grain as well as by 

 the weevils themselves acts as a narcotic on the weevils, eventually 

 kilhng them, but exercises no detrimental efi'ect on the grain unless 

 it is stored for longer than two years, when its germinating power 

 becomes affected. The time taken to bring about the complete 

 destruction of the insects seems to depend chiefly upon the relative 

 volume of air present. 



Edkins (J. S.) & Tweedy (N.). Report on the Effect of various 

 Gaseous Reagents upon the Flour Moth {Ephestia kuhnieUa) and 

 other Pests found in Flour. — Rept. Grain Pest ( War) Comtnittee, 

 Royal Society, London, no. 4, April 1919, pp. 3-13. [Received 

 17th July 1919.] 



Experiments, directed chiefly against Ephestia huhniella, but 

 including Tribolium castaneum, T. coyifusum, Gnathocerus cormitus, 

 Laemophloeus pvsillus and Tenebroides mauretanicus, were made 

 with various gaseous reagents, of which formaldehyde was not efiective; 

 1 per cent, sidphur dioxide killed all stages of Ephestia in half an hour, 

 but rendered the flour useless for bread-making ; 5 per cent, ammonia 

 had no effect on beetles or larvae ; ether sprayed by an atomizer 

 anaesthetised the insects ; methylated spirit did not give immediate 

 results, but all life was extinct by the next day. 



Ozonised air containing 100 parts of ozone per million killed the 

 moths after two exposures of from 7 to 8 hours each, 50 parts per 

 million in dry air tended to destroy the moths but not the larvae. 

 Although these are not destroyed, they are unable to continue develop- 

 ment. The apparatus used for this experiment is described. As 

 5 parts of ozone per million is injurious to human life this treatment 

 would have to be carried out in closed circuits. 



Dendy (A.) & Elkington (H. D.). On the Phenomenon known as 

 "Webbing" in stored Grain. — Rept. Grain Pest (War) Committee, 

 Royal Society, London, no. 4, April 1919, pp. 14-17. [Received 

 :17th July 1919.] 



This phenomenon which was formerly considered to be to some extent 

 evidence that the grain beneath it was in good condition has now 

 been proved to be the result of the wanderings of thousands of larvae 

 of the flour moth, Ephestia elutella. over the grain. As Ephestia elutella, 

 is only one of many insects capable of producing such a web, all 

 similar conditions cannot however be attributed to this pest. The 

 damage done by the larvae consists in eating out the germ from the 

 stored grain and fouling it by faecal products and other debris. The 

 former injury is not very serious, as it takes place almost entirely 

 within 12 inches of the surface of the heap, and the latter would be 

 removed in the ordinary cleaning process to which all wheat is subjected. 

 There is slight evidence of the web serving as a trap for weevils. 



