14 
THE RED SPIDER ON HOPS IN CALIFORNIA. 
LOCOMOTION. 
In order to determine the probable distance that an adult female 
mite is capable of crawling in one day, experiments were conducted 
in the laboratory. A sheet of paper 3 by 4 feet was placed in front 
of a window in a warm room, a female mite placed in the center of the 
paper, and its progress followed with a pencil for one hour. (See 
40. 7 J 
Fig. 5. — Track of a red spider on blotter, covering a distance of 40 feet 9 i nches and representing movements 
during one hour. Sacramento, Cal., 1912. (Original.) 
fig. 5.) In two cases loose soil was placed on the paper. Table II 
sums up the results. 
Table II. — Distance traveled by adult female red spiders in one hour on smooth paper 
and on loose soil. 
Ex- 
peri- 
ment 
No. 
Surface used. 
Distance 
traveled. 
Distance 
gained. 
1 
Ft. in. 
22 4 
23 8 
3 7J 
Ft. in. 
2 
do 
3 
.... do 
2 
4 
o m 
5 
20 5 
15 9 
40 9 
6 2 
6 
do 
7 
do .. 
8 
21 1 
o m 
6 2 
The surface of the paper corresponds very well with that of the 
hopvine, and at this rate an average female mite is capable of cover- 
ing 211 feet of vine surface during a period of 10 hours. 
