34 BULLETIN 707, U. S. DEPARTMENT OF AGRICULTURE. 



Ill addition to the foregoing tests tobacco powder containing 0.85 

 per cent nicotine was burned in a box at the rate of 6 ounces to 360 

 cubic feet. None of the 15 larvae used in this box fumigation were 

 killed in 19 hours. The strength was increased to 26 ounces to 360 

 cubic feet with the result that 20 per cent of the larvae were killed. 



Effect on eggs. — A solution containing 40 per cent nicotine extract, 

 used at dilutions of 1 part mixture to 25 and 1 to 50, killed nearly 

 all the eggs, while dilutions of 1 to 75 and 1 to 100 were not effective. 



It appears from these tests that the various forms of nicotine are 

 of no practical value against carpet beetles. 



MISCELLANEOUS SUBSTANCES. 



Effect on carpet-heetle adults. — Oil of cedar leaves effectively pro- 

 tected flannel from carpet-beetle infestation in laboratory-cage tests. 

 Lavender flowers were ineffective in such tests. Formaldehyde fumi- 

 gation (2-| ounces to 360 cubic feet) proved ineffective against adults. 



Effect on larvce. — Miscellaneous sitbstances tested against carpet- 

 beetle larvae and found to be more or less effective are as follows : 



Alcohol (ethyl), 50-95 per cent solutions. 



Cloves ( powdered ) . 



Gasoline (undiluted). 



Mercuric chlorid (1 pound to 50 gallons of water). 



Sulphur (burned), 81 ounces to 360 cubic feet. 



Miscellaneous substances found to be ineffective against larvae are 

 as follows : 



Hellebore (dust). 

 Lavender flowers (dust). 

 Lime (dust). 

 Pepper, black (dust). 

 Sodium fluorid (dust). 

 Sulphur (dust). 



Alcohol (ethyl) 20 to 40 per cent solu- 

 tions (sprayed). 

 Allspice (dust). 

 Arsenious acid (dust). 

 Borax (dust). 

 Formaldehyde (fumigation). 



Effect on eggs. — Solutions of ethyl alcohol at 30, 50, 70, and 100 

 per cent appeared to prevent the hatching of carpet-beetle eggs. A 

 20 per cent solution, however, was of no value. 



Borax, gasoline, mercuric chlorid (1 pound to 50 gallons of water), 

 and sulphur failed to prevent hatching of eggs. 



HEAT. 



Effect on carpet-heetle larvce. — Tests of the effect of heat were 

 conducted by placing 10 larvae on flannel in an incubator for varying 

 lengths of time. The results are shown in Table IX. 



