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



larvae in these jar tests it was concluded that the naphthalene killed 

 much more effectively and rapidly when the fumes were confined b}'" 

 covering the jars. 



In trunk tests against larvae fresh flannel and 25 larvaj, half- 

 grown, were placed in a lantern globe, the two ends of which were 

 covered with cheesecloth. This lantern globe was placed in a trunk 

 of average size, in which najjhthalene flakes at the rate of one-fourth 

 pound to 5 cubic feet were sprinkled, and the lid closed. The use of 

 the lantern globe was to prevent the naphthalene from coming in con- 

 tact with the larvae, so that any action noted on the larvae would be 

 from the effects of the fumes. Examination at the end of 32 days 

 showed that all the larvae were dead. The flannel was found to be 

 very slightly eaten, showing that some of the larger larvae had, no 

 doubt, survived long enough to feed slightly. A duplicate test was 

 made, in which naphthalene balls were used at about the same rate, 

 with identical results. In an untreated trunk, serving as a check, to 

 which the same number of larvae had been added, were found many 

 adult moths and more than a hundred larvae, and the flannel was 

 badlj- eaten. 



The results of these tests indicate that the killing effect of the 

 naphthalene is due principally to the fumes. 



A second series of trunk tests Avas made, using three trunks of 

 average size, in which larva? were added at intervals during the 

 course of the experiment. In trunk No. 1 three-fourths pound of 

 naphthalene flakes was scattered over the flannel and the bottom of 

 the trunk. Ten larvae, half to full grown, were added every 2 weeks 

 for 10 weeks, making a total of 50 larvae used. Two months after 

 the last lot of larvae was added examination showed that none had 

 pupated, there had been only very slight feeding on the flannel, and 

 all had been killed. 



In trunk No. 2 one pound of naphthalene balls was used, and larvae 

 were added from time to time as in the test with trunk No. 1. The 

 results were the same as those obtained in the use of naphthalene 

 flakes, except that there was no feeding on the flannel, which was due, 

 no doubt, to the fact that a larger quantity of balls tha» flakes was 

 used. 



In the check trunk (trunk No. 3). at the close of the experiment, 

 numerous moths and larvae were found and the flannel Avas badly 

 eaten. 



naphthalene: effect on clothes-moth eggs. 



Pieces of flannel about 1 iuch square, containing 10 or more clothes- 

 moth eggs, were thoroughly dusted with naphthalene flakes and 

 placed in two open battery jars. Observations made 10 days later 



