1921] Riley: Responses of Water-Strider 261 
the animal so that it arouses from the death-feint. Then 
again, this species may arouse from the feint without any 
visible external stimulation. 
Severin and Severin (1911, pp. 8, 9) state that the legs or 
parts of the legs of a feigning Nepa apiculata may be cut off 
without disturbing the animal. During the death-feint, this 
species may be cut through the prothorax and both parts of the 
body will remain quiet. But a feigning insect immediately 
arouses when dropped onto the surface-film of water. These 
Fig. 11. The large water-strider, Gerris remigis Say, alate form; 
a typical surface-film, running water inhabitant. Natural size. 
(Drawing by Beutenmiiller). 
investigators (1911, p. 13) remark, with reference to ten 
individual Nepa apiculata, that: 
Every specimen was made to feign by taking it out of the water 
with a pair of forceps, dropping it upon a moist blotter from a small 
height and turning it over and over laterally three or four times. 
In another connection they (1911, p. 16) state that: 
The death feint of Belostomas often ends suddenly when the insects 
are thrown into water; frequently, however, the bugs bob up to the 
surface of the water and continue to feign there. 
With reference to the death-feint of Nepa apiculata, men- 
tioned by these writers (191la, p. 100) in the second of their 
papers, there is the statement that: 
When raked out of the water, together with the mud and partially 
decayed vegetation, these insects usually feign death, in which condition 
they readily escape detection, as their flat bodies are effectively concealed 
by the black mud and decaying plant tissue. 
Regarding the origin of the death-feigning response, Severin 
and Severin (1911, pp. 37-38) make the following statement: 
