256 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



which the disease is most widespread, are now investigating the life 

 history and habits of this tick and we may soon look for important 

 developments. It is of course necessary that the host or hosts which 

 harbor the infection in nature be discovered before it can be deter- 

 mined whether preventive measures will consist in dealing with the 

 animal or animals that harbor the infection or with the tick that trans- 

 mits it. In order to determine the source of this infection, it appears 

 to be necessary that ticks, either sufficiently engorged to molt or to 

 deposit eggs, be collected from their various host species and engorged 

 in the following stage or stages upon a susceptible host, such as the 

 guinea pig. When we consider that the mortality from the disease 

 is as high as 70 per cent, the danger that is entailed in the investiga- 

 tion is at once appreciated. 



The brilliant work of Dr. H. T. Ricketts in connecting the tick now 

 known as Dermacentor venustus with the transmission of the disease 

 has well been rewarded in the award of a gold medal by the American 

 Medical Association at the annual meeting held in June. 



Even field mice appear to play a role in the multiplication and dis- 

 semination of ticks. During the recent examination of the Bureau of 

 Entomology collection an engorged larval specimen that appeared to 

 be Dermacentor variaMlis was found with a label to the effect that it 

 had been collected from the nest of a field mouse near "Washington, 

 D. C. It will undoubtedly be found the world over that birds and 

 small mammals serve as hosts for the immature stages of various 

 Ixodid ticks. In a country like Africa, where numerous tick-borne 

 diseases obtain, the imi^ortance of these habits will at once be appre- 

 ciated. That more has not been learned concerning them is due in 

 part, as before stated, to their small size and the fact that they readily 

 escape notice in the thick fur and feathers or drop before an examina- 

 tion can be made. There is much that remains to be learned about 

 these relations through a more extensive collection, and it is hoped that 

 entomologists and other collectors may extend their activity in this di- 

 rection. 



In connection with life history studies, geographical and host lists 

 are being prepared in connection with which this subject will be con- 

 sidered more extensively. Any collections, records or data on the 

 subject will be gratefully received. 



Since this paper was presented a work entitled ''Interim Report on 

 the Parasites of Grouse," by A. E. Shipley, has come to hand, which 

 gives some important information concerning the host relations of the 

 European Castorbean Tick {Ixodes richms) in England. On page 5 



