LIFE HISTORY OF CATTLE TICK. 83 
viable. With between 24 and 48 hours’ submergence the number of 
ticks that recovered diminished rapidly. Occasionally specimens 
recovered after a period of submergence of over 48 hours. For 
instance, the specimen collected on July 12 and submerged for 50 
hours survived and deposited viable eggs. Later in the season (that 
is,.in October) somewhat, different results were obtained in experi- 
ments in the submergence of adults. In this month many ticks 
recovered after from 50 to 90 hours of submergence. In fact, fully 50 
per cent of the ticks submerged between these extremes regained 
their full activity. In one experiment two out of five ticks sub- 
merged in October for 91} hours recovered and deposited viable eggs. 
Nevertheless a number of ticks submerged for 115} hours did not 
recover. 
The results that have been mentioned above indicate that where 
engorged ticks fall from cattle that are standing in permanent pools 
of water none will survive to deposit eggs. At the same time the 
results show that temporary flooding of from 24 to 100 hours’ duration 
would not in all cases prevent ticks from depositing eggs. It must 
be noted in this connection, however, that the vitality of eggs depos- 
ited by ticks just prior to temporary flooding would not be interfered 
with by the water, although, of course, they might be washed away. 
DROPPING FROM HOST. 
It is a more or less prevalent popular idea that ticks have some 
sense which enables them to drop from a host in places favorable 
for oviposition. A few observations have shown, as was supposed in 
the beginning would be the case, that there is probably no such 
power of perception present in the cattle tick. The popular impres- — 
sion probably had its origin in the fact that bunches of seed ticks are 
found most numerously in the places where the cattle collect for the 
benefit of shade or water. This phenomenon obviously is due merely 
to the collecting and standing of the cattle. 
Many observations seem to show clearly that there is no preference 
as to the time of dropping. In our experiments many ticks have 
been known to drop from host during the night and many others to 
~ drop during the day. 
LOCOMOTION. 
Some attention has been paid to obtaining data on the distance 
engorged ticks may travel after dropping from the host, since this 
has a practical bearing on double fencing in eradication work. In 
some experiments specimens were placed on the floor in the laboratory 
and allowed to move at will. The total movement varied from 24 
inches to 123 inches, the latter distance being covered in 52 minutes. 
5795—No. 72—07 
3 
