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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 12 



exhaustive trial or that it should be generally adopted, but the results 

 indicate that it may furnish a very rapid and convenient means of 

 reducing the numbers of lice to a point where they will no longer be 

 a serious problem. 



It is hoped that some reader may be in a position to give this method 

 a thorough test on a commercial scale. 



Naphthalene Nest Eggs 



The following tests were made to determine the value of naphthalene 

 nest eggs which have been recommended as efficient agents for the 

 control of lice on laying and setting hens. 



Laying Hens. In these tests the eggs were placed in the nest used 

 by laying hens which were known to be very Jousy, and the hens were 

 examined every week until they ceased to lay. 



Table III gives the results of these tests. 



Table III. The Results of Tests with Naphthalene Nest Egos Against Lice on Laying Hens- 



This table shows that naphthalene nest eggs are of no value against- 

 Uce on laying hens. 



Since the length of time that a laying hen would remain on the nest 

 and exposed to the action of the nest egg would vary with the indi- 

 vidual hen and with the number of eggs laid during the test, further 

 experiments were made to determine the effect of what was considered 

 to be a maximum exposure. A box just large enough to hold a hen 

 but in which it could not stand up, was made. The bottom of this 

 box was covered with excelsior on which a naphthalene nest egg was 

 placed. Two one-inch holes were bored in one end of the box to fur- 

 nish ventilation. A hen, badly infested with lice, was placed in this 

 box and the hd was closed so that the bird was forced to remain on 

 the egg for about thirty minutes on the following dates : September 6, 

 7, 8, 10, 11 and 14. At the close of this experiment the hen was found 

 to be as badly infested with lice as before treatment. This experiment 

 was duplicated, using nest eggs containing 46.4 per cent and 6.9 per 

 cent of naphthalene and the same results were obtained. 



Setting Hens. In the tests against lice on setting hens the nest 

 egg was placed with the setting of eggs and allowed to remain there 

 during the entire experiment. 



