406 
Psyche 
[September-December 
swiftly through the foliage, sometimes breaking into a series of leaps 
and dashes that carried them long distances along the top of low- 
growing vegetation in a few seconds. Thus, these animals usually 
remained in the herbaceous stratum; only occasionally did an in- 
dividual plunge downward and hide near the ground. 
Penultimate L. punctulata were seen in the fall in the same fields, 
and typically traveled through the herbaceous stratum when dis- 
turbed. At night these spiders were seen resting on or moving 
slowly upon the vegetation or, much less frequently, upon the ground. 
Laboratory studies. — The results of our study of diurnal stratum 
selection by undisturbed female L. rabida in an artificial habitat are 
summarized in Fig. 5. (Temperature was 25-26° and relative hu- 
midity > 60% throughout the 10 days.) During the 20-hr survey, 
the spiders were on the cardboard foliage 73% of the time. Most 
of that time the animals rested motionless on one of the “leaves” at 
an average height of 0.12 m, i.e., more than half-way up the “plant.” 
The long axis of their bodies was usually in a plane ranging from 
nearly horizontal to a slope of about 6o° from the horizontal. In 
the latter situation the spider faced up- or downward. In those 
cases in which the spider rested vertically on a “stem” the spider 
INDIVIDUAL 
Fig. 5. Stratum selection by female Lycosa rabida in an artificial 
habitat. During 20 hr, spread over 10 days, we recorded the proportion 
of time spent on cardboard foliage (solid bar) vs. on the ground. At half- 
hr intervals within observation periods, we also measured the height of 
those spiders that were on the foliage (hatched bar). 
