146 E. MELVILLE DuPORTE 



The results obtained with Tychius picirostris agree in general 

 with those obtained by other workers. 



Influence of Temperature on the Death Feint. Heat. — Insects 

 feigning death were placed on their backs on a warm iron* 

 plate, the temperature of which was not high enough to be 

 unbearable to the tips of one's fingers. Without a single excep- 

 tion the insects immediately became active and attempted to 

 turn over and escape. It was impossible to produce the feint 

 by dropping the insect on the hot surface. When the plate 

 became cooled to a temperature slightly above that of the room, 

 the feint, however, could be induced without difficulty. Insects 

 dropped several times alternately on the warm plate and on 

 the surface of the table feigned death in the latter case but 

 would not on the heated surface. 



Cold. Several individuals were placed in a refrigerator regis- 

 tering a temperature of 11° C. The feint could be very readily 

 elicited and the duration was much greater than at room tem- 

 perature. The duration of the initial feint varied from 55 

 seconds to 4 minutes and 35 seconds. The variability of the 

 duration of successive feints was as marked as at room tem- 

 perature, as may be seen from the following figures, which give 

 the duration (in seconds) of the first five feints of one individual : 



55, 40, 140, 385, 50 



Other individuals were tested on a plate of thin glass placed 

 on a block of ice. The feint lasted for periods ranging from 

 nineteen minutes to upwards of an hour. At the end of an 

 hour those which had not recovered spontaneously were removed 

 to the table, where they immediately became active. On first 

 being placed on the cold plate the insect becomes somewhat 

 restive but does not actively struggle. After a short while the 

 legs slowly and gradually relax, the degree of relaxation varying 

 with the different individuals. In this condition the legs are 

 never pressed against the body but their attitude resembles to 

 some extent that of the limbs of the dead insect. 



Cold alone, without mechanical shock, can produce a condi- 

 tion similar to that of the death feint. If an insect struggling 

 on its back is placed on the cold glass plate it will after a while 

 cease to struggle, become quiescent and assume a position similar 

 to the feigning insects. This raises the question as to whether 



