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



Thirty adults, with a large piece of flannel, were inclosed in a 

 trunk, to which had been added cedar chips at the rate of one-half 

 pound to 9 cubic feet. At the end of 8 weeks all the adults were 

 dead and no larvae were present. The check trunk showed 10 live 

 larvae and the flannel slightly eaten. 



Adults placed in closed battery jars with flannel treated with 

 cedar chips resulted in the killing of 80 to 100 per cent in 7 days. 



E-ffect on larvm. — Ked-cedar chips were placed in a trunk at the 

 rate of one-half pound to 9 cubic feet. Twenty-five half to full- 

 grown larvae were added and the trunk closed immediately. At the 

 end of 56 days no larvae were dead, and the flannel was considerably 

 eaten. 



E-ffect on eggs. — Red-cedar chips were used in open battery jars 

 against the eggs. After 9 days larvae were observed on the flannel, 

 but were not counted. 



Apparently red-cedar chips were not very effective against the 

 different stages of the carpet beetle. Clothing would be protected 

 by the use of cedar chips only when used very liberally. 



-ii *^'"- 



PYBETHRUM POWDEE. 



E-ffect on larvcB and eggs. — Pyrethrum powder was used in four 

 tests against larvae on flannel in open battery jars. An average of 

 27.5 per cent was killed in about a week. 



Two tests were conducted with pyrethrum powder against larvae 

 on flannel in large-stoppered bottles. Of a total of 20 larvae used, 

 90 per cent were killed in about one week. Fifteen per cent of the 

 larvae on untreated flannel in stoppered bottles died in the same time. 



Two pieces of flannel, each containing 10 or more eggs, were 

 placed in battery jars and dusted with the powder. At the end 

 of 26 days no larvae were found on the treated flannel, although the 

 eggs may have hatched and the young larvae have been killed almost 

 immediately. An average of 13 live larvae was found on the un- 

 treated pieces of flannel. 



Pyrethrum powder proved considerably less effective against car- 

 pet-beetle larvae than against clothes-moth larvae. 



HTDBOCARBON OILS AND OIL EMULSIONS. ' " ' ' ' 



Effect on carpet-heetle adults., larvce.^ and eggs. — A 10 per cent 

 solution of carbolic acid showed moderate protective value against 

 carpet-beetle adults in cage tests, while a 5 per cent solution proved 

 ineffective. 



Mineral oils and oil emulsions of the nature of kerosene killed all 

 the larvae when used undiluted. The oil emulsions proved effective 



