70 
Psyche 
[March 
was seen in the adolescent amrantias of 1935. Stimulus 
from above (often the only way to give a bilaterally sym- 
metrical stimulus, owing to the “screen”) is apparently 
among the factors, but individual difference at least as 
much so. The aggressive patterns of 10 were especially 
conspicuous (fig. 1). 
The following indicates the distribution of responses to 
all fork-to-dorsum stimuli recorded 7-18-36 to 7-31-36 (9 
individuals) : 
per cent shuttle spread reach seize other imperceptible 
Stimulus from above (18) 11 11 17 33 17 11 
Stimulus lateral (102) 38 13 20 11 12 5 
These figures compare as follows for responses of 7-12-36 
and for those subsequent to 7-31-36 (10 individuals) : 
per cent shuttle spread reach seize other imperceptible 
7-12-36 (114) 82 8 8 0 3 0 
after 7-31-36 (52) 17 33 11 23 4 11 
With regard to accessory responses, the situation is sim- 
ilar to that of 1935. Reaching, spreading or seizing may 
precede the shuttling, but in the 1936 series, the response 
most frequently combined is reaching rather than spreading. 
Reaching and spreading again appear, as in 1935, as the 
shuttling response becomes extinguished. Dropping, a re- 
sponse prominent in the literature of such-like stimulation, 
is nearly absent from these observations, but from its 
rare instances, and experience with it in other species, 
it is surmised to be a response more characteristic than 
shuttling among individuals younger than have here come to 
observation. 
Only one instance is recorded of shuttling to a stimulus 
other than fork-to-dorsum ; this was on the touching of a leg 
by an electric vibrator (not the “buzzer” mentioned in the 
previous report; 11, 8-8-36). This vibrator, made from an 
electric bell, was little applied as a “to dorsum” stimulus, but 
gave evidence of being a weaker stimulus than either of the 
forks. 
In conclusion, the evidence for shuttling as a pattern dis- 
tinctive of A. aurantia among the species of present study, 
