24 
NORTH AMKKICAN FKVKK TICK AND OTHER SPECIES. 
proper, are waved through the air more or less constantly, and vio- 
lently when a moving object approaches. The ticks attach them- 
selves to any animate or inanimate object which touches them. Only 
those that happen to attach themselves to cattle (and rarely a few- 
other animals) ever develop; the others either die or, dropping oil", 
become widely scattered. 
Heavy rains wash the seed ticks to the ground, and it is possible 
that violent winds may also serve to disseminate them. In our 
experiments they have thus been spread to a distance of 5 or 6 feet. 
It is noticeable that the seed ticks shun direct sunlight. We have 
repeatedly seen bunches move halfway around the support with the 
shade. In the morning they would be on the west and at night on 
the east side. 
EFFECT OF WATER ON SEED TICKS. 
Interesting data having a bearing on the dissemination of the cat- 
tle tick through the agency of water courses have been obtained. It 
has been noted that heavy rains wash seed ticks from their supports 
to the ground. In a considerable number of experiments seed ticks 
were found to endure submergence varving in different lots from 
10 days to 157 days. The latter record was obtained in an experi- 
ment in which seed ticks were first placed in water in a Petri dish 
and a few days later removed to a tube witli earth on the bottom. 
The details of these experiments are given in Table IV. 
It is doubtless true that dissemination by water courses is not 
quite as important as these results would indicate. Of course it is 
possible that seed ticks may be carried many miles and deposited 
on grass or bushes, from which they may reach cattle. The enor- 
mous scattering of ticks so submerged in water, as would be the case 
in floods, would undoubtedly greatly reduce the chances of infesta- 
tion in pastures. 
Table IV. — Effect of water on seed ticks. 
Eggs hatched. 
Sept. 2... 
Oct. 4-11. 
Sept. I... 
Aug. 1G-1 
AUg. 21-2 
Aug. 4-11 
Seed ticks 
submerged. 
Sept. 4. 
Sept. 30 
Nov. 11 
Sept. L. 
Aug. 4. 
Aug. 17 
Aug. 21 
Sept. 4. 
Longevity, 
submerged. 
Days. 
47 
157 
14 
12 
41 
32 
17 
10-17 
Remarks. 
Bight inches of water in tub. 
In Petri dish; Oct. 9 removed to tube with dirt on bot- 
tom. 
Alive on Nov. 25, and may have lived longer. 
In tub with sand and vegetable matter. 
In l'etri dish on poreh. with algSB in water. 
In I'et ri dish on laboratory d< - . 
Submerged as eggs. 
Submerged as eggs. Culicid larva may have interfered. 
Some years ago Professor Morgan obtained interesting results on 
the effect of low temperature on seed ticks. In brief, he found a 
temperature of 15° or 16° F. for a short period did not kill many seed 
