78 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



been inspected here in Washington there was another shipment of 

 3,000 ornamental flowering cherry trees sent by the city of Tokyo to 

 rephice the former shipment, and that after inspection these trees 

 were found to be free from injurious insects, although examined 

 individually with great care. They have been planted in the District 

 of Columbia. 



WORK ON INSECTS AFFECTING THE HEALTH OF MAN. 



The investigation carried on by the Bureau of Entomology on the 

 Rocky Mountain fever tick was completed during the year and the 

 results published. The investigation showed that the proper treat- 

 ment of certain domestic animals will probably result in the practical 

 extermination of this disease in the infected regions. 



A very interesting investigation has been begun concerning the 

 possible relations of biting insects to the carriage of pellagra. 

 These investigations have been carried on for the most part in the 

 State of South Carolina in cooperation with the Postgraduate Med- 

 ical School of New York City. It is well known that claims have 

 been made by an English investigator, Sambon, working in Italy, to 

 the effect that pellagra in that country is probably carried b}'^ the 

 bite of a gnat of the genus Sim/uUum flying from patients affected 

 by the disease to healthy persons. The investigations which have 

 been carried on in South Carolina, however, seem to indicate that, 

 in this country at least, if pellagra should be shown to be carried by 

 any biting insect, the insect concerned in this transmission in South 

 Carolina is very much more probably the biting stable fly or biting 

 house fly {Stomoxys calcitrans) than any of the resident species of 

 the genus Simulium. This conclusion is especially significant in view 

 of the recent announcement by the experts of the Harvard Medical 

 College that they have secured experimental proof of the transfer of 

 infantile paralysis by this same species. 



WORK ON THE W^HITE FLY IN riX)RIDA AND ON OTHER ORANGE INSECTS. 



The investigation of the white fly in Florida has made substantial 

 progress and is nearing completion. The parasites imported from 

 India have apparently died and have not become established in 

 Florida, but inexpensive and effective methods of spraying have been 

 found and are now being used and promise to settle in a satisfactory 

 manner the problem of direct control. Demonstration work is now 

 going on. 



Work on the orange thrips being carried on in California has 

 resulted in the finding of satisfactory spraying methods, and, after 

 demonstration on a large scale, these methods have been adopted by 

 the orange growers. 



