1936] Orbweavers’ Responses to a Tuning-Fork 11 
stances in which they appeared, are in general as follows: 
Dropping: As often reported, the spider, on the near ap- 
proach of the fork, drops any distance from a few inches, to 
the substratum; returns after a very variable interval. In 
these observations not a characteristic response to the vi- 
brating fork in any position. It is more so in smaller species, 
and is seen in exceptional individuals among the present. 
Among them, it is more usual in response to a relatively 
massive stimulus. 
Folding: The spider immobilizes, with legs folded 
against body, the miscalled “death-feint.” In Epeiras as- 
sociated with dropping; not a normal response to present 
fork stimulation; as here seen, rather a product of other, 
and more massive accidental stimulus. 
Shifting: The spider being at rest, moves the feet some- 
what, but does not change its station. A response apparent- 
ly arising when the fork, however presented, does not make 
on the receptors enough impression to set up any of the 
more differentiated responses noted below (cf. Schaxel, 
cited by Griinbaum, p. 287). Most strikingly seen in col- 
onies of E. cavatica; a vibrating fork touched to a strand 
often elicited shifting through the colony generally, a few 
of the nearest making actual start for it. 
Approaching : The spider resting at orb-center or in re- 
treat, moves as to attack the fork held in contact with orb. 
Normal for all present species when resting at orb-center 
(Details on E. diademata, Peters, ’31, p. 735). Less posi- 
tive in long-matured (senescent?) individuals. For spiders 
in retreat (Boys; Barrows, p. 318) : First movement (to 
center) frequent for E. cavatica, occasional for E. trifolium, 
E. domiciliorum (probable individual difference) ; less fre- 
quent for E. insularis, though on occurrence, relatively vio- 
lent. 
Shaking and/or Arching: The spider, resting at orb- 
center, arches legs, moving abdomen away from web ; shakes 
web, sometimes for a whole minute, (function, cf. Barrows, 
p. 320; for E. diademata, Griinbaum, pp. 295, 297). Seen 
here most in early adult A. aurantia to fork held near ven- 
ter, with orb between. Young A. trifasciata normally tilted 
the abdomen away from the fork, held to venter or dorsum. 
Shuttling: The spider, resting at orb-center, moves 
