248 
Psyche 
[September-December 
johnsoni suddenly began to run, the H. hesperolus ran out the 
door and onto the nest, circled the P. johnsoni from behind, 
and arched its body and legs over the facing salticid. The P. 
johnsoni struck repeatedly, and the gnaphosid’s fangs were ex- 
tended. As the P. johnsoni slowly backed off the nest, with its 
first pair of legs raised, the H. hesperolus slowly followed, with 
arched body, until reaching the edge of the nest. When 6 cm 
from the motionless gnaphosid on the nest, the P. johnsoni turned 
180° and ran away. 
6. As the P. johnsoni courted at one door, the H. hesperolus 
departed from the opposite door and ran across the nest toward 
the salticid. Simultaneously, the P. johnsoni turned 180° and 
ran. The H. hesperolus overtook the salticid 1 cm from the nest, 
circled its victim, with its body arched, and repeatedly hit the 
salticid with its extended fangs. After standing with its first pair 
of legs raised for approximately 30 sec, the P. johnsoni became 
immobile, whereupon the H. hesperolus inserted its fangs into 
the side of the carapace and fed. 
In a related species, Herpyllus blackwalli, Bristowe (1958) 
noted that the fangs are usually buried at the junction of the legs 
on the side of the prey, consistent with the present observations 
on H. hesperolus. He described the predatory behavior of an- 
other gnaphosid, Drassodes lapidosus, in great detail, noting the 
extremely rapid speed with which the spider moved, arching of 
the body, and circling the prey. In this species, a band of silk 
is laid over the prey’s legs as the predator circles, something not 
witnessed for H. hesperolus. Another point of interest is that 
in Bristowe’s observations, D. lapidosus preyed, in the laboratory, 
on a number of other spider species of comparable size, although 
he did not stage interactions with salticids. Remember that the 
spiders found with dead P. johnsoni in the field were a species 
of Drassodes. 
During the observation in which the P. johnsoni did not touch 
the nest, the H. hesperolus was standing in the nest door, facing 
outward, apparently motionless. The P. johnsoni faced the H. 
hesperolus, while 7 cm away, and slowly approached. When 
3 cm away, the P. johnsoni began to back slowly; and when 5 
cm away, a 180° turn was made, then the P. johnsoni walked 
rapidly away. A possible interpretation is that the P. johnsoni 
