350 ANNUAL EEPOKTS OF DEPARTMENT OF AGRICULTUEE. 



Entomologists of the board, working under the direction of the 

 Bureau of Entomology, have examined 485 cases. This work necessi- 

 tated making 1,552 tests, and comprised the use of many thousand 

 insects, representing insects frequenting the household, infesting vege- 

 tation, man, other animals, etc. The work also involved the testing 

 relative to injurious action of insecticides on vegetation. In addition 

 to the actual testing of proprietary insecticides, a large number of 

 tests have been made of the various ingredients entering into the 

 composition of insecticides to determine whether they were active or 

 inert. These entomologists have also made various scientific investi- 

 gations to obtain basic facts to aid in the enforcement of the law, as, 

 for example, studying the action of naphthalene, sodium fluoride, 

 different pyrethrum powders, tobacco powders, vegetable oils, etc., 

 on insects, when used as dusts, sprays, or fumigants. The conditions 

 under which many so-called liquid lice-killers will or will not be 

 effective and the causes of injury to vegetation by certain kerosene 

 emulsions have been made the subject of careful study. 



While the information obtained by these special investigations is 

 primarily used in the enforcement of the insecticide act and the 

 general results have been published from time to time in the Service 

 and Eegulatory Announcements of the board for the benefit of the 

 trade, a more detailed publication may be made by the bureau inter- 

 ested in bulletins of the department or in scientific journals of the 

 United States. 



