140 
Psyche 
[June 
stage, the male climbs over her, and uses the forelegs to help turn 
her abdomen to the side. When the genital pore, which lies on the 
ventral abdomen, is thus exposed, the male inserts his palpus. After 
2-3 min., the male withdraws this pedipalp, turns the female’s abdo- 
men in the other direction, and inserts the other pedipalp (fig. 2010, 
Kaston, 1948). 
Raising the forelegs and holding the abdomen to one side are by 
no means specific to courtship. This display occurs to a wide variety 
of objects that are approaching too close to the spider: other spiders 
■ — regardless of sex (Crane, 1949), houseflies or other large prey, 
models of prey that are about the size of the spider, such as 9-12 mm 
spheres, or even the end of a finger or a pencil. In these situations, 
however, the spider with its forelegs raised and waving backs off while 
facing the moving object and, when 5-8 cm away, turns away and 
flees. In intraspecific encounters, the effect of raising the forelegs is 
to bring the other spider to an abrupt halt, whether it be a wandering 
cagemate, a courting male preparing to touch the female, or a female 
stalking or about to jump at the male. Indeed, raising of the forelegs 
appears to have this ‘stop-sign’ effect even in encounters between 
congenerics of the three Phidippus species. Drees, working with 
female Salticus scenicus, was able to initiate hunting behavior by 
moving a black dot along a white wall, and to stop the pursuing 
spider by moving wires projecting from the side of the model through 
an angle that imitated the waving of the forelegs (Drees, 1952). 
Female P. coccineus and P. apacheanus are unusual in that they 
perform an acceptance dance just before the male touches them. With 
forelegs high and wide apart and abdomen bent to the side, the 
female sways before the male, sometimes with a few steps to one 
side and then the other. In other Phidippus species, the female rejects 
the male by extending the first pair of legs whenever he approaches 
too closely, and merely fails to ward him off when she is ready to 
accept him. 
Differences in the display of the three Phidippus species remain to 
be investigated. At this stage, it is apparent that subtle quantitative 
differences are involved. For example, while P. apacheanus moves 
his forelegs both closer and higher as he nears the female until the 
Explanation of Plate 9 
Figs. 13 - 16. Phidippus apacheanus Chamberlin and Gertsch. 13. Juve- 
nile, total length 9 mm. 14. Adult male below, female above, total length of 
each 11.5 mm. Both male and females are black with bright orange dorsum 
of carapace and abdomen, and with iridescent green chelicerae. 15. Male 
signalling female. 16. Male signalling and facing female. 
