246 
Psyche 
[September-December 
All four P. johnsoni pulled the nest and struck at the gnapho- 
sids. One bumped and another stabbed. Each P. johnsoni also 
walked and turned frequently inside the nest. In three cases, 
the H. hesperolus ran away from the nest after the P. johnsoni 
struck. In one case, this was after 3 min in contact with the nest; 
contact was for between 15 and 30 sec in the other two cases. 
For the remainder of the observation period, in each of these 
cases, the P. johnsoni remained inside the nest and the H. hes- 
perolus remained at the other side of the cage. 
During one observation, the H. hesperolus killed and con- 
sumed the P. johnsoni after 18 min on the nest. Intermittently, 
the gnaphosid inserted its fangs into the silk and pulled on the 
nest by raising its cephalothorax. Eventually, a hole was torn 
through the nest. The P. johnsoni repeatedly struck at the gna- 
phosid through the hole. Suddenly, the P. johnsoni walked 
rapidly through the nest, with the H. hesperolus following a 
parallel path on the outer nest surface. Arriving at the nest door, 
the P. johnsoni began to depart the nest, but at the moment when 
its anterior cephalothorax was only barely out the nest door, 
the H. hesperolus leaped from the top of the nest and hit at the 
carapace of the P. johnsoni with its extended fangs. With its 
body and legs arched over the P. johnsoni , the H. hesperolus 
made repeated predatory attacks, consisting of rapidly and brief- 
ly lowering its cephalothorax, with fangs open, making contact 
with the carapace of its victim. The P. johnsoni made several 
strikes at the enveloping H. hesperolus, but soon it became rela- 
tively immobile, with its forelegs raised. After 30 sec, the P. john- 
soni was motionless, presumably dead or paralyzed. The H. 
hesperolus pulled with its fangs inserted in the silk in the vicinity 
of the door, eventually ripping the nest open somewhat. Ap- 
roximately 1 min later, the gnaphosid inserted its fangs into the 
prey’s carapace near the junction of the legs and began to feed. 
Interactions Between Phidippus johnsoni Males and 
Herpyllus hesperolus That Occupy Nests of Phidippus 
johnsoni Females 
P. johnsoni females with eggs were forced from their nests. 
When H. hesperolus were placed in the cages, they soon entered 
and remained inside the nests with the eggs. The next day a P. 
