DEATH FEIGNING REACTIONS IN TYCHIUS PICIROSTRIS 143 



than two hours, fifty-three representing the largest number of 

 feints successively produced in a single individual." l 



The results obtained with Tychius picirostris did not differ 

 markedly from those of Gee and Lathrop with the plum cur- 

 culio, but the period during which the feint could be succes- 

 sively elicited was not so great, varying from a few minutes 

 to somewhat over an hour. 



Repeated stimulation results in a reduction of the average 

 duration of the feints, although the duration of one of the later 

 feints may be greater than that of some occurring earlier in 

 the succession. The following table gives the average dura- 

 tion of the first ten feints of four individuals as compared with 

 that of all succeeding feints. In computing the averages, cases 

 in which the insects did not respond are omitted. If these were 

 included the average duration of the later feints would be 

 much lower. 



TABLE II 

 Average Duration (in Seconds) of Earlier and Later Feints 



There is a certain irregularity to be noted in the later feints. 

 With few exceptions, in cases where a long succession of feints 

 was obtained, the first several attempts to produce the feint 

 were successful. Later, however, the number of unsuccessful 

 attempts increased until finally the point was reached at which 

 the feint could no longer be elicited. 



When the limit of successful response was reached the method 

 of producing the shock stimulus was changed to discover whether 

 this would have any effect in inducing the feint. It was found 

 that in most cases either the insect did not respond, or it re- 

 sponded in the first few trials only. Only in one case did I 

 succeed in obtaining a long succession of feints by changing 

 the method of evoking the feint after the insect had failed to 

 respond to the first means employed, and in this case seventy- 

 six per cen t were partial feints. 



1 Gee and Lathrop. Death Feigning in Conotrachelus nenuphar Herbst. Annals 

 Entomological Society of America, 1912, 5, 391-399. 



