THE ROCKY MOUNTAIN SPOTTED-FEVER TICK. 177 
22 and August 25, 1908, lived between 250 and 290 days. The 
greatest longevity among a large number of lots of ticks which 
became adult during 1909 was between 320 and 353 days. This 
record was made on a single male which molted between August 30 
and September 1, 1909, and died between July 18 and August 18, 
1910. The other lots which became adults during 1909 lived 
between 117 and 321 days. Among over a hundred lots, the molting 
of which was observed by us during 1910, the longevity ranged 
between 66 and 367 days. The majority of these lots contained 
some individuals which lived over 250 days and a considerable 
number showed a longevity of over a year. 
Still more remarkable is the longevity exhibited by lots of adults 
collected in Montana during the spring of 1910 by Mr. W. V. King, 
before they had attached to hosts. Among the several lots observed 
the longevity varied from 55 to 413 days. Four of these lots which 
were obtained from shrubbery between March 18 and May 31, 1910, 
lived more than 320 days. The greatest longevity observed 
occurred in a lot of one male and two females collected at Victor, 
Mont., April 2, 1910. One female lived until May 20, 1911, or a 
period of 413 days. It should be borne in mind that these collected 
individuals undoubtedly came to maturity in the fall of 1909 and 
passed the winter in hibernation. Therefore we should add about 
six months to the longevity observed, making a total longevity of 
about 600 days. It is thus apparent that ticks which become adult 
in the latter part of the summer may survive until the second spring 
following. Adults collected from animals during the spring and 
summer of 1910 were found to live between 40 and 262 days. The 
females in these lots varied from unengorged to about one-eighth 
engorged. The length of the life of the sexes appears to be about 
the same. 
All longevity records are based on ticks kept in tubes on moist 
sand in the laboratory. 
There is a marked tendency for adults which are awaiting a host 
to climb to a considerable height on shrubs or trees so that they are 
in a position to be brushed off by large animals when passing. When 
disturbed they either grasp any passing object with the forelegs, or 
curl the legs up, drop, and catch hold of any object which they 
happen to strike in falling. When one moves an object near speci- 
mens which are awaiting a host, the ticks begin to extend and wave 
the forelegs, the other legs also being frequently extended. Engorged 
females also use the legs for feelers in their search for suitable piaces 
for concealment In one case an engorged female was observed to 
extend and wave all of the legs but one, which was used to cling to 
the inclined surface upon which it was crawling. 
21448°—Bull. 106—12——12 
