BUREAU OF ENTOMOLOGY. 647 



its investigations in cooperation with the State Agricnitiiral Experi- 

 ment Station of ^Montana and with the Bureau of Biological Survey 

 of the United States Department of Agriculture. 



With the practical completion of the work on the spotted-fever 

 tick, it became possible to devote some attention to other species of 

 considerable economic importance, upon which only general observa- 

 tions had been made. Work was begun on the fowl tick, which is a 

 serious pest in a large area of the southwestern portion of the United 

 States. At the same time the spinose ear tick was taken up. This 

 creature is the cause of the loss of a large number of calves in Texas, 

 New Mexico, and Arizona. 



The work on the accumulation of data regarding the life history 

 of the species which transmits splenetic fever of cattle was con- 

 tinued. This consisted largel}' of experiments to determine the lon- 

 gevity of the different stages of the tick under different environ- 

 ments. This work has been of great practical value in connection 

 with the eradication of the cattle-fever tick in the United States, and 

 it has progressed to the point where it will soon be possible to issue 

 a bulletin on the points in the life history of the species, which must 

 be taken into consideration in the work of eradication that is now 

 under way. 



Studies on the life history of a number of species of minor impor- 

 tance were completed and the results placed in the form of a publi- 

 catioii. Incidentally observations were made upon several other pests 

 of live stock, including the horn fly and the screw-worm, which will 

 lead to the formation of plans for better control of these species in 

 the future. 



INVESTIGATION OF POSSIBLE TRANSMISSION OF PELLAGBA BY INSECTS. 



Attention was called in the last report to the announcement by 

 Dr. Sainbon that in Europe a species of Simulium is the probable 

 agent in the transmission of pellagra. During the fiscal year, at the 

 request of the State board of health of South Carolina, two agents 

 of the bureau were sent to that State to investigate the subject. They 

 had been occupied in determining the distribution of sand flies with 

 reference to the locality in which pellagra is known to have origi- 

 nated. For various reasons the theory proposed by Dr. Sambon is 

 of doubtful validity. Nevertheless there seem to be indications that 

 the disease may possibly be transmitted by certain insects if not by 

 sand flies. For this reason the investigations of the bureau have 

 dealt with a number of species of biting insects which are to be found 

 commonly in localities where pellagra occurs. Much material was 

 collected, but down to the present time there are no definite indica- 

 tions that pellagra is an insect-borne disease. It is, however, neces- 

 s-arv to do much more work before any reliable conclusions can be 

 reached. 



WORK ON INSECTS INJURIOUS TO STORED PRODUCTS. 



Work on insects injurious to storod products has been performed, 

 as previously, under the immediate direction of Dr. F. II. Chitten- 

 den. Many practical tests huve been made of the value of bisulphid 

 of carbon and hydrocyanic-acid gas. 



