( ^v ) 



destroyed the germinating power, it is to be presumed that 

 the conditions of test were not entirely favourable to the 

 grain, as I am told that wheat dried and exposed to heat 

 under conditions of free transpiration of moisture can with- 

 stand a temperature of 120° C. I am surprised, however, 

 that the authors do not refer to the heat necessary to destroy 

 the insect pests. They deal with a number of chemical and 

 some mechanical devices for destroying the insects, or freeing 

 the wheat from them. Cannot dry heat be used ? So far 

 as my knowledge goes, the few insects which have been ex- 

 perimented on die at temperatures of 45° to 52° C. (= 113° 

 to 125"6° Fahr.). Is it known whether the Coleoptera destruc- 

 tive of grain are specially adapted to heat, or is there some 

 other reason which precludes this apparently simple and 

 economical remedy being used ? 



Mr. J. C. F. Fryer said that he had worked out these tem- 

 peratures pretty thoroughly, and found that 130°-140° Fahr. 

 was always fatal to insects; their power of resistance was, 

 however, very varied, and moist temperature proved less fatal 

 than dry. 



The President observed that in some French books a 

 method was described for destroying grain weevils without 

 interfering with the germinating power of the wheat. Water- 

 house had experimented successfully on cotton. 



Mr. Main pointed out that if the wheat was to be used for 

 food, its germinating power was of no moment. 



Mr, WiLLOUGHBY Ellis observed that 104° Fahr. was 

 always fatal to Staphylinid beetles. 



Mr. DuRRANT suggested that heat was most fatal when 

 applied in shocks ; but Mr. Bacot said that he had not found 

 this to be the case with mosquito larvae. 



Dr. Chapman narrated an incident that occurred to him 

 many years ago, when, having immersed a number of beetles 

 in boiling water to kill them, a specimen of Carabus clathratus 

 had recovered the next day, and eaten most of the other 

 insects. 



Gift of a Microscope. 



The Secretary said that Mr. E. E. Green had offered to 

 the Society a valuable Binocular Microscope, for which objec- 



