36 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
reached the trail. To prove or disprove this possibility, one hundred 
ticks, marked with white paint, were liberated one hundred feet above 
the trail on May 3, all at the same point. Unfortunately, it seemed, 
at the time, this whole area was burned over on May 4. One of my 
assistants, however, when going up the trail on May 23, found three of 
these marked ticks along the upper edge of the trail, these ticks having 
survived the fire and moved downward. The places were carefully 
marked, and we returned the next day, and again found the ticks, 
though they had changed their position up or down the trail. The 
two outermost were more than two hundred feet apart. 
A similar experiment carried on in another place with two hundred 
ticks showed that a majority of ticks tend to migrate down a slope and 
that very few go up. Some, however, remained near the point of 
release during two successive seasons, 1918 and 1919. None were 
found more than twenty feet up the slope, nor more than two hundred 
and fifty feet down the slope. 
The tendency of ticks to concentrate along a trail or road crossing a 
slope, or along the edge of cultivated land similarly situated has been 
observed in numerous instances, the details of which need not be 
recorded at this time. 
As a further proof that these adult ticks move about, it may be 
mentioned that we often removed all the ticks from a tuft of grass on 
the edge of Big Creek trail, mentioned above, only to find it again 
infested on our next trip. The writer has also seen ticks drop from a 
grass blade or bush and deliberately move toward a person standing 
nearby. 
Though the observations thus far made have only been of a pre¬ 
liminary nature, they have been sufficient to indicate that ticks do 
move about, and that the tendency when on a slope is to migrate down¬ 
ward, and that migration is hindered when the low vegetation is at all 
abundant. Under certain highly localized conditions, this fact has 
valuable application to control work. Other applications to the whole 
general problem may develop as a better knowledge is gained of the 
movements and the factors which control them. 
A Reaction of Engorged Seeds to Light 
Prof. R. A. Cooley determined some years ago that engorged imma¬ 
ture ticks dropped from their host during daylight. During August of 
the past season, while feeding seed ticks on a cottontail rabbit, a chance 
observation developed the further fact that the rapidity of dropping 
could be increased or decreased by varying the degree of light intensity. 
By placing the infested animals in darkness dropping could be stopped, 
while by increasing the light intensity, the rate of dropping could be 
