June, '09] JOURNAL OF ECONOMIC ENTOMOLOGY 255 



restral birds probably playing the more important role in their dis- 

 semination. 



Amhhjomma dissimile is a species found on iguanas in Central 

 America and Mexico. During the past year it was collected at 

 Brownsville, Texas, by Mr. H. P. Wood of the Bureau of Entomology 

 from iguanas that had been brought from the isthmus of Tehuan- 

 tepec for exhibition purposes. It is supposed that the host relations 

 of this species are similar to those of A. tuherculatum, for nymphs as 

 well as adults were collected from the iguanas. Larvge and nymphs 

 have attached to and engorged upon a bovine, but adults would attach 

 to a cold-blooded host only. 



Fortunate it is that birds do not play the role of host to the Cattle 

 Tick, else our national campaigTi of extermination would be in vain. 

 As far as we know, except in the case of A. americanum, these bird- 

 host relations are not of economic importance in this country, at least 

 at the present time. Should a tick-borne disease be introduced and 

 one of these species become implicated, birds might be an important 

 factor in its spread. 



Aside from some of the larger mammals, the host relations of the 

 Spotted Fever Tick (Dermacentor venustus Banks) still remain to be 

 determined." During the past year we have found all stages of this 

 tick to engorge upon a bovine. While there are no records of birds 

 serving as hosts for any species of Dermacentor, such a possibility, as 

 well as that of reptiles and batrachians, must be considered. Sus- 

 picion is most naturally placed upon the small mammals as harborers 

 of the spotted fever infection, since it seems most probable that they 

 serve as hosts of this tick and play an important role in its dissemina- 

 tion. Dr. H. T. Ricketts in connection with his investigation of the 

 disease and Prof. R. A. Cooley,'^ as the entomologist of the state in 



'A report by Doctor Ricketts of investigations made during 1907 and 1908 

 into the cause and prevention of Rocky Mountain Spotted Fever in the Bitter 

 Root Valley of Montana has recently appeared (February, 1909). In it Doc- 

 tor Ricketts states that he has found by inoculation that the gopher, rock 

 squirrel, wood chuck, chipmunk, and mountain rat are susceptible to the 

 disease and also serve as hosts for the Spotted Fever tick. Experiments with 

 the tick are said to indicate that at least the first four of these hosts may, 

 when acting in conjunction with the tick, be effective in maintaining the 

 disease by causing its extension among the ticks. The host or hosts of the 

 infection in nature, however, has not as yet been discovered. 



'In a report of his investigations of the Spotted Fever Tick in 1908, which 

 appeared in April, Prof. R. A. Cooley includes data on its host relations. All 

 of six Rocky Mountain Pikas {Lagomys princeps) and two of the twelve chip- 

 munks (Tamias quadririttatus amcotiiis) collec-ted had immature ticks upon 

 them. None were found upon any of twenty Red or Pine Squirrels (Sciurus 

 Jiudsonicus) collected. 



