AprRIL 19, 1912] 
may be held by any tibia or femur in such a 
manner that the weight of the entire insect is 
sustained by the extensor muscles of an indi- 
vidual segment of one leg. In the case of 
Nepa many interesting details are given con- 
cerning preliminary movements immediately 
prior to the termination of the feint. If 
Belostoma is mutilated by snipping off small 
portions of the appendages, the animal quickly 
comes out of the death-feint after one or two 
repetitions of the excision. Nepa acts quite 
differently. The legs may be cut off one at a 
time, and even the tip of the abdomen, with- 
out any movement on the part of the organ- 
ism. 
TI. It was found that the duration of the 
feint varies considerably in different individ- 
uals. One group of Belostomas were put into 
thirty-eight death-feints; after this they re- 
fused to respond. After having been placed in 
water for a few moments, they again dis- 
played the reaction. This was repeated again 
and again until the insects no longer feigned 
death. “The average time that all of the 
Belostomas feigned throughout all the series 
of successive death feints was eight hours.” 
In other experiments, it was found that the 
responses, in both Belostoma and Nepa, be- 
came weaker toward the end of the series; also 
that the duration of the death-feint decreased 
in a succession of trials; and that the cause of 
the cessation of the response, in each series of 
experiments, while partly due to fatigue, was 
more largely the result of the dryness of the 
body while exposed to the air. 
IV. Dryness tends to decrease and damp- 
ness to increase the length of the death-feint. 
If Belostoma is placed upon the surface-film, 
or below the water surface, the duration of the 
feint is diminished. When Belostoma is 
thrown into the water, it usually comes out of 
the death-feint immediately. Sometimes, how- 
ever, the creature will bob up to the surface of 
the water and feign in that position. 
V. The duration of the death-feint dimin- 
ishes in both species when exposed to high 
temperatures. At a low temperature the re- 
sponse is lessened in Belostoma. In Nepa, on 
SCIENCE 
629 
the other hand, a low temperature prolongs the 
death-feint. These facts were ascertained 
while the insects were exposed to the atmos- 
phere. Experiments were also undertaken 
with the view to discover what the result 
would be on the death-feigning reaction when 
the animals were transferred from water to the 
atmosphere. It was found that the duration 
of the feint is lessened when the transition 
was from water at a low temperature to the 
atmosphere with a temperature lower than 
12° ©. In both Belostoma and Nepa the 
death-feint considerably decreases at a low 
temperature. 
VI. If Belostomas are exposed to sunlight 
the length of the death-feigning reaction 
diminishes. In certain experiments with arti- 
ficial light it was discovered that both Belos- 
toma and Nepa are aroused more quickly 
when subjected to a bright light than was the 
case with a weak light. A moving light 
arouses both species sooner than a stationary 
one. The death-feint in Nepa is much di- 
minished when the creature is exposed to a 
bright light, if the organisms had previously 
been kept in the dark. 
VII. The authors call attention to the work 
of Robertson on spiders, Hpeira producta? 
and Amaurobius sp.? This author found that 
the “sham-death” reflex may be induced in 
the above active species “by the thoracic 
ganglia alone, or even by the ganglia of the 
posterior or two anterior segments of the 
thorax alone. . . . With the supra- and sub- 
cesophageal ganglia removed the reaction is still 
carried out in the active species, but it is now 
weaker, has a longer latent period (in Hpeira 
sp. at least, and probably in Amaurobius sp.) 
and it is a rhythmically interrupted tetanus.” 
In this same connection the work of Holmes on 
Ranatra is quoted. If the head of Belostoma 
is removed with a pair of sharp scissors, the 
creature generally continues to feign death. 
Decapitated specimens will often swim freely 
in the water after arousing from the feint. 
On removing the supra-esophageal ganglion 
most of the organisms continued the death- 
feint; but the usual tension of the body and 
