EXPERIMENTS AGAINST CLOTHES MOTHS. 



27 



As will be noted, sulphur burned in the form of a candle, at the 

 rate of 208 grams to 360 cubic feet, killed all adults in 18 hours. The 

 combination of sulphur and carbon in equal parts, when burned at 

 the rate of 228 grams to 360 cubic feet, killed 50 per cent of the 

 adults in 18 hours. Sulphur fumes killed larvae in house fumigation 

 when used at the rate of 213 grains to 360 cubic feet, but was in- 

 effective at weaker strengths. 



Formaldehyde in solution and in crystalline form (paraformal- 

 dehyde) failed to kill a majority of the adults and was of no value 

 against larvae. 



HEAT. 



Effect on clothes-moth larvce. — The effect of heat on larvae was 

 tested by placing the infested flannel in an incubator. Ten larva? 

 were used in each case, with the results shown in Table VI. 



Table VI. — Effect of heat on clothes-moth larvce. 



Length of 



Degree of 





exposure. 



heat. 





Minutes. 



°F. " 





6 



128 



All killed. 



11 



120 



Do. 



31 



110 



Do. 



11 



110 



30 per cent killed. 



31 



105 



20 per cent killed. 



A single test made by exposing a piece of flannel containing many 

 larvae in the sun for six hours, the developing temperature ranging 

 from 80° F. to 105° F., resulted in the death of all larvae. 



Effect on eggs. — The effect of heat on clothes-moth eggs was tested 

 in the same manner as described above for larvae, 10 or more eggs 

 being present on each piece of flannel. See Table VII. 



Table VII. — Effect of heat on clothes-moth eggs. 



Length of 



Degree of 



Result. 



exposure. 



heat. 





Minutes. 



°F. 





6 



128 



All killed. 



6 



125 



Do. 



11 



120 



Do. 



31 



110 



Do. 



11 



110 



None killed. 



31 



105 



Do. 



A single test made by exposing for six hours a piece of flannel con- 

 taining many clothes-moth eggs to the sun in the same manner as 

 described for larvae resulted in the killing of the eggs. The tem- 

 perature of the flannel during the exposure rose from 80° F. to 

 105° F. 



