96 
Psyche 
[March 
dried leaves. Three of the four glass walls of each terraria were 
shielded with white paper on the outside to minimize external visu- 
al distractions. Each terrarium was covered with glass to prevent 
escape and to maintain relatively constant humidity conditions 
(24.5°C ± 1.0 SD; 60.0% R.H. ± 2.0 SD). Water was available ad 
libitum from cotton-plugged vials, and food consisted of larvae 
of the yellow mealworm beetle Tenebrio molitor offered twice 
weekly. Photoperiod consisted of 16-17 hr of continuous artificial 
light alternated with 7-8 hr of continuous darkness. 
Data Collection 
Observations were conducted from early June through late July, 
1973, and data collection began 5-7 days following marking of the 
animals. Each observation terrarium rested on a styrofoam block 
placed on a separate table from the recording equipment to reduce 
vibrations, and I was positioned 45 cm in front of the chamber. 
Protocol during all male-male interactions was tape-recorded and 
data were transcribed at a later date. Following transfer to the 
observation terrarium, subjects were observed for 10 consecutive 
days at approximately the same time. The frequencies of each be- 
havior comprising the agonistic behavioral repertoire of S. crassipes 
during adult male-male interactions (Aspey, 1976b) were recorded 
continuously throughout the observation period. Since the dura- 
tion of each observation period varied with the number of spiders 
present (with N=2 the observation period lasted 20 min; with N=3, 25 
min; with N=5, 35 min), the data were adjusted to yield mean fre- 
quences of each behavior per 20 min. 
An interaction was considered to occur when one spider ap- 
proached within 3-5 cm of another spider; data were discarded 
when two spiders simply passed one another without orienting or 
displaying to one another. An interaction was considered to con- 
tinue when one spider chased or pursued a retreating spider. An 
interaction was considered terminated if an animal fled or was 
actively driven away by another spider. An interaction was con- 
sidered to involve only two spiders because interactions among 
three or more spiders occurred only twice. 
Transitional Probabilities 
To determine predictable behavior sequences for individual 
spiders, an intra-individual transition probability matrix was con- 
