1976] 
Jackson — Phidippus johnsoni 
247 
johnsoni male was introduced through a hole in the cage. Once 
the P. johnsoni responded to the H. hesperolus, observation 
was continued for 15 min. In six of the seven observations, the 
P. johnsoni touched the nest, whereupon he began to perform 
type 2 courtship. Since the elements of this type of courtship 
have been described in detail elsewhere (Jackson, 1976), only 
brief descriptions of the major elements will be provided here. 
Probe. The first pair of legs are moved alternately forward and 
backward, with the tarsi in contact with the nest. 
Vibrate. The tarsi of the first pair of legs are always in contact 
with the silk; the other legs may or may not contact the nest. 
A series of extremely rapid, low amplitude, dorsal-ventral move- 
ments are performed, which have the appearance of a sudden, 
faint blurring of the spider and the silk in his vicinity. 
Grip Vibrate. The spider vibrates while his fangs are inserted 
into the silk. 
Tug. While gripping the silk with his fangs, the spider moves 
his cephalothorax alternately dorsally and ventrally, over a dis- 
tance of a few millimeters. 
Since the result of each interaction was different, each will 
be related briefly. 
1. As the P. johnsoni courted, the H. hesperolus departed by 
the opposite door and ran away. 
2. The H. hesperolus remained inactive as the P. johnsoni 
courted. After the male entered the nest, the gnaphosid departed 
by the opposite door and ran away. 
3. The P. johnsoni entered the nest after courting, with the 
H. hesperolus remaining mostly inactive. Once inside the nest, 
the gnaphosid began to walk, whereupon the P. johnsoni de- 
parted the nest and backed away. When 3 cm from the nest, 
the P. johnsoni turned 180° and ran away. 
4. As the P. johnsoni probed at the nest door, the H. hesperolus 
approached, whereupon the P. johnsoni backed away 1 cm. For 
one min the two spiders stood motionless, facing each other, 
the gnaphosid partly out the nest door. Suddenly, the P. john- 
soni turned 180° and ran, with the H. hesperolus making a brief 
dash toward the male, covering a distance of 1 cm before stopping 
then returning to the nest. 
5. As the P. johnsoni courted on the nest, the H. hesperolus 
began to walk and turn actively inside the nest. When the P. 
