1981] 
Edwards — Phidippus mystaceus 
211 
engage the substrate, the cymbium containing the files is actively 
moved against the plectrum on the tibia. When the palpus is fixed 
on the substrate with the macrosetae, again it is the cymbium that is 
moved against the stationary plectrum. 
Other Types of Vibratory Signaling 
A third method of sound production in spiders, vibration (pro- 
ducing a “buzz” similar to that of a fly), has been demonstrated for 
the sparassid spider, Heteropoda venatoria (L.) (Rovner, 1980). In 
the same paper, low amplitude appendage oscillations resulting in a 
faint whirring sound were reported for Lycosa rabida Walckenaer. 
Phidippus whitmani Peckham and Peckham employs entire-body 
(?) vibration (lacking an audible component, but with a widely- 
spaced stance similar to H. venatoria ) during its Type I visual 
courtship (Edwards, 1980). This is probably an adaptation to its 
microhabitat (mesophytic leaf litter), the same substrate used for 
vibratory signaling by many lycosids. I have noted another vibra- 
tory behavior that also seems similar to that of H. venatoria during 
the Type II tactile courtship of Phidippus regius C. L. Koch, while 
the male is contacting the nest of the female (Edwards, 1975). 
Subsequent laboratory observation showed a similar behavior for 
P. whitmani, although the timing of vibratory sequences was 
different from those of P. regius, probably a species-specific differ- 
ence. Jackson (1977) reported a similar behavior for P. johnsoni 
(Peckham and Peckham) and suggested a similarity in some respects 
to the vibratory courtships of web-building spiders. I suspect that 
the vibratory courtships of Phidippus species, although not pro- 
ducing an audible component that I could detect, may be more like 
the courtship of H. venatoria than like web-builders, or perhaps all 
3 groups produce vibrations in essentially the same way (i.e., 
“juddering” as in araneid males; Robinson and Robinson, 1980). It 
is curious that all known forms of non-tactile direct inter-individual 
communication not involving vision in salticids are acoustic or 
vibratory signals (despite the contention of Crane, 1949, and other 
authors, the use of airborne pheromones by salticids has never been 
proven). In the case of P. mystaceus and P. whitmani, both visual 
and vibratory signals are used simultaneously, although the 2 
species produce vibrations in different ways. 
