145 



nearest water. In this respect, therefore, G. fusca is unUke G. palpalis, 

 but resembles G. pallidipes, G. brevipalpis and G. morsitans. The 

 haunts of G. brevipalpis, G. pallidipes and G. fusca are situated ahnost 

 exclusively along roads and paths. 



Particulars are also given of the relative numbers of the sexes in 

 the species captured. It is noteworthy that of some 5,000 examples 

 of G. brevipalpis only 50 were females. 



Parker (KR.). Some Results of Two Years' Investigations of the 

 Rocky Mountain Spotted Fever Tick in Eastern Montana. —J^. 



Eco7i. Entom., Concord, N.H., xi, no. 2, April 1918, pp. 189-194. 



Much of the subject matter of this paper has already been noticed 

 [see this Review, Ser. B, v, p. 80], but mention is here specially made 

 of four small mammals that act as hosts of the Rocky Mountain 

 spotted fever tick [Dermacentor venustus]. 



Of these, the first in importance is the jack rabbit, the only animal 

 known to harbour all three stages of the tick, and also able to maintain 

 an infestation of ticks without the presence of domestic animals. 

 Other reasons that render it important are its general distribution 

 in all parts of eastern Montana, its wide travelling radius, its suscepti- 

 bility to Rocky Mountain spotted fever, and the fact that it may 

 play an important part in the spread of the disease both extensively 

 and intensively. Nymphal forms of the tick may be present in large 

 numbers and engorge in much less time on the jack rabbit than on 

 any other host. Cottontail rabbits are also important as hosts of 

 the immature stages. The frequent coincidence of the abundance 

 of ticks and the abundance of jack rabbits has been noticed in seasons 

 preceding the occurrence of cases of the fever. The interval between 

 the epidemics is variable, but is frequently seven years, though it 

 may be more or less. The occurrence of fever following a parallel 

 increase in rabbits and ticks is of interest and indicates the possible 

 control of spotted fever under eastern Montana prairie conditions by 

 the eradication of rabbits. 



There is a probability that porcupines, when numerous, might 

 prove to be important adults hosts, as more than 20 adult ticks have 

 been found on a single animal, and a seasonal average of 6*8 was 

 observed in 1917. 



The deer mouse is the second most important wild mammal in 

 eastern Montana in relation to the tick. The reasons for this are 

 that as a host of immature ticks it exceeds in abundance all other 

 wild mammalian hosts combined, and is adaptable to all sorts of 

 conditions. The degree of infestation of these mice varies from 125 

 ticks on a single mouse to "19 under prairie conditions in a poor tick 

 season. 



Field mice are not in any way comparable to deer mice as hosts, 

 being of importance only where very favourable habitat conditions 

 occur. In recording the infestation of mice allowance must be made 

 for the fact that the mice are trapped before 11 o'clock at night, or 

 even earHer, leaving ample time for the ticks to leave the hosts before 

 the traps are examined in the morning. 



(C480) B 



