252 Annals Entomological Society of America  [Vol. XIV, 
The different phases of behavior that have been discussed, 
such as crawling into the various hibernating quarters which 
have been enumerated, the crowding together into clusters, 
and the motionless state in which the gerrids lie, are due in 
part, if not largely, to contact responses, although there have 
been accumulated certain facts that seem to indicate that 
the crawling into winter quarters may be partially the result 
of a tendency toward negative phototaxis at the hibernation 
period. However, more evidence is needed on this point. 
These gerrids seem to be responsive to contact stimuli not 
only during the hibernation period, but also at its inception. 
Apparently, both the dorsal and ventral surfaces are sensitive 
to contact as well as the legs and lateral sides of the body. 
Frequently, they have been found in piles of dead leaves 
(Figs. 5, 6, 7, 8, 9) with their bodies in such positions as to 
suggest evidence for the above statement. Their bodies were 
in contact with a leaf above and with a leaf below, the legs 
being stretched out as nearly as possible in the same plane as 
that of the body. The legs and bodies of the insects appeared 
to be rigid and they were so to the touch of the fingers. It was 
possible to lift the body of a gerrid by means of the posterior 
pair of legs, without bending them, the animal remaining 
perfectly stiff and motionless while this was done. All of this 
was very suggestive of the death-feigning response—briefly 
discussed later in this paper—which is induced, certainly in 
part, by contact stimuli. The gerrids evidently had crawled 
into the masses of leaves through the interstices formed between 
the different individual leaves (Figs. 6, 7, 8, 9). Such move- 
ments brought not only the upper surface of the body in contact 
with the leaf or leaves above this surface, but it also brought 
the lower surface of the body against the leaf or leaves below 
this latter surface. In many instances it was clear that the 
spaces between the leaves were so small that the water-striders 
could not have walked erect into the interstices (Figs. 6, 7, 8, 9), 
but must have raised their legs almost to the same plane as that 
of the body and almost parallel with its longitudinal axis. In 
fact, not infrequently, individuals have been found with their 
appendages exactly in the position described. 
However, there is considerable positive evidence with respect 
to the points just discussed. On several occasions the gerrids 
have been observed, after they had left the surface-film, walking 
