RED CEDAR CHESTS AGAINST MOTH DAMAGE. 7 



May 5-7 were still unhatched. Examination May 21 determined that 

 all eggs had hatched. Of 739 eggs deposited May 6-7 and held as 

 checks in the laboratory outside of chests, 465 were hatched May 14 

 and 274 on May 15. 



(10) On May 7, 1921, 46, 13, and 107 eggs deposited, respectively, 

 May 4-5, 5-6, and 6-7, were introduced in Chest No. 2. Examination 

 on May 11 determined that 1 egg only of those deposited May 4-5 

 had hatched. Examination on May 21 showed that all eggs had 

 hatched. Of 267 eggs deposited May 4-5 and held as checks in the 

 laboratory outside of chests, 89 were hatched May 12 and 178 on 

 May 13. Of 336 deposited May 5-6 and held as checks in the labora- 

 tory outside of chests, 111 were hatched on July 13, 146 on May 14, 

 and 79 on May 18. 



EFFECT UPON LARViE. 



The effect of cedar chests upon larvae of clothes moths varies with 

 the age and growth attained by the larvae when they are subjected 

 to the action of the chests. It has been taken for granted in popular 

 entomological literature that larvae become fully grown during warm 

 weather in from 4 to 10 weeks, but there are no authentic cases re- 

 corded of clothes moths actually reared from egg to adult at any 

 season of the year in less than four months. 



Observations made in the laboratory at Washington, D. C, during 

 1920 and 1921 indicate that no definite statement can be made con- 

 cerning the time it will take clothes-moth larvae to become fully 

 grown, since their growth varies tremendously when they are fed 

 upon the same material or upon different materials. 



These statements seem necessary to indicate to the reader why one 

 can not judge the age of a clothes-moth larva by its size. Clothes- 

 moth larvae do not mature as fast as has been thought. It is well to 

 understand that larvae that have become one-half to full grown, re- 

 gardless of the time required to attain this growth, have been able 

 to cause so much damage and to leave behind them in their feeding so 

 much webbing (PI. II, B) and sandlike frass that their presence can 

 be detected by a casual examination of the affected garments. Ex- 

 ception is made of certain fur garments where the feeding larvae lie 

 buried beneath the fur close to the skin; but even in this case the 

 falling of the severed fur will readily reveal damage. 



Garments should not he placed in chests without first having been 

 beaten, brushed, and sunned to remove the larvae. This treatment, 

 advised as a preliminary for all materials intended for storage in 

 cedar chests, if painstakingly done should remove even younger and 

 -mailer larvae. Any larvae remaining, however, and entering the 

 chests with the clothing arc apt to be very young or very small. 

 This is a most important fact, as cedar chests kill only very young 

 tnall larvae. 



Since cedar chests fan not be depended upon to kill half to full 

 grown larvae, such articles as halls of yarn, floor skins backed with 



woolen cloth, infested pillows stuffed with hair or feathers, and simi- 

 lar article-, all portions of which can not he brushed on ;ill sides, 

 might better !«• treated \>y fumigation or- other' methods (<> kill older 



larva- before being placed in cedar- chests. Other-wise these articles 

 may he fed upon somewhat in cedar chests )>y the older larva', until 



they have transformed into moth:-, hut will be protected thereafter. 



