1912] Conotrachelus Nenuphar Herbst 397 
chloroform, carbon di-sulphide, and carbon-di-oxide with simi- 
lar results. Mutilated specimens put into the death feint were 
also tested and it was found that the most of them responded 
in the same manner. Thus in the case of the gases, as in that 
of heat, we see an adaptive feature in the nature of the instinct 
that tends to remove the animal from a stimulus of such a 
character as would result in injury to the organism. 
Effect of Mutilations. 
Holmes (6) found in Ranatra, that the appendages could be 
removed one by one, while the animal was in the death feint 
without evoking any response from the insect. The Severins 
(10) found in Belostoma that “‘if one of the limbs be snipped in 
two with a pair of fine scissors, the bug may not respond at all, 
or the limb may twitch or quiver, or the insect may right itself 
and scramble eagerly to get away. One or two repetitions of 
this experiment with those specimens which did not come out 
of the death feint immediately after the cut was made were 
sufficient to bring them out.’’ In the case of Nepa, however, 
the results were more in accord with those reported on Ranatra. 
The appendages of eight feigning curculios were removed 
one by one. With the exception of two of these curculios, 
every one of them showed absolutely no signs of recovery from 
the feint until several minutes after the operation. In the case 
of these two, recovering activity took place immediately after 
severing the first appendage. They were very easily made to 
feign again, and the operation proceeded without any apparent 
objection on their part. 
seven feigning individuals were decapitated with a pair of 
small, sharp scissors. The result was an immediate relaxation 
of the legs followed by efforts on the part of the body to right 
itself. In one case the wings were outstretched as though 
attempting to fly. The bodies were placed in the normal posi- 
tion with the result, however, that only two of them walked in 
a co-ordinated manner, and these for only a short time. This 
behavior is no doubt due to the shock effects of the operation. 
It was found possible to induce the death feint in these decapi- 
tated specimens, but with much more difficulty and with a 
shorter period in the duration of the response than was the case 
in the normal specimens. 
