36 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



continue and death follows. This is well shown in the destruction of 

 the bean weevil larva?, and the pupal stages of the Hessian fly^ by 

 drought. 



Continued exposure to moist air does not seem to produce death 

 directly but rather to encourage digestive troubles^ and to supply 

 the conditions for the destructive growth of parasitic fungi as was the 

 case with the third test of the bean weevil. 



Naturally, the inability of the bean weevil to reproduce in moisture of 

 26 per cent and below led to an examination of dry air as a means of 

 sterilizing and preserving bean seeds from weevil injury. 



The first set of experiments, which bore at all on this point, were 

 laid out for an entirely different purpose, but the data from them bears 

 on this matter sufficiently to justify their introduction. Five glass 

 museum jars each with a capacity of one liter were selected and into 

 the first was poured 250 cc. of concentrated sulphuric acid of specific 

 gravity 1.83, into the second a mixture of 125 cc. of distilled water and 

 125 cc. of concentrated sulphuric acid, into the third a mixture of 83 

 cc. of acid and 167 cc. of water, into the fourth 250 cc. of distilled 

 water and into the fifth nothing whatever. Into each of five wide- 

 mouthed two-ounce bottles were introduced enough white beans to 

 cover the bottom, and 25 healthy specimens of the bean weevil. The 

 mouth of each bottle was covered with gauze and the bottle suspended 

 from the inside of the glass cover which was then clamped on the jar 

 on a rubber gasket. 



In slightly more than one month after the experiment started the 

 jars were opened and the beans examined. In the jar having 250 cc. 

 of acid all weevils were dead and the beans free from injury. In the 

 jar having 125 cc. of acid and 125 cc. of water the same condition was 

 found. In the jar having 83 cc. of acid and 167 cc. of water living 

 beetles of the second brood were found and many of the beans had been 

 perforated. In the jar having 250 cc. of distilled water both weevils 

 and beans were destroyed by fungi. In the jar having air only, a 

 large brood of second brood beetles were found and most of the beans 

 were perforated. 



It thus appears that reproduction of the weevil in tightly closed 

 jars can be prevented by the introduction of sufficient concentrated 

 sulphuric acid to keep the atmospheric humiditj^ low. 



The second experiment relative to the utilization of a dry atmosphere 

 to destroy bean weevil was planned for that specific purpose. Ten 

 glass museum jars each of one liter capacity were chosen and a two- 



1 Headlee, Thos. J., and Parker, J. B., L. c, p. 108-109. 



2 Standfuss, M., Handbuch fiir Sammler der europaischen Gross-Schmetterlinge, 

 1891. 



