CATALEPSY IN" THASMIDAE SCHMIDT. 505 



phenomena taken together, represent what we call catalepsy. With 

 the severance of the connection between the nervous system and the 

 head ganglia the possibility of this phenomena vanishes. 



As to the causes producing this specific excitation of the nervous 

 system the author can not say. All his attempts at producing it in 

 active insects failed. They entered it more readily when left alone, 

 showing the causes are internal and the author therefore calls it 

 " autocatalepsy." 



The author believes that the "death feigning" phenomenon is 

 intimately associated with catalepsy and hopes soon to compare that 

 of Ranatra with Carausius. He thinks it will be found that the im- 

 mobility of caterpillars mimicking twigs and of Mantis in awaiting 

 prey are similar phenomena. Finally, even hibernation may be 

 related to it. 



From the biological standpoint, the cataleptic quiescence of phas- 

 mids is only a specific adaptation of the muscular and nervous sys- 

 tems for the purpose of mimicking still portions of plants. 



Compared with usual animal immobility, catalepsy is at an ad- 

 vantage: First, economy of energy, no fatigue developing; second, 

 suppression of reflex action which might expose the insect. 



This adaptation is most interesting and remarkable. It is not 

 morphological, but physiological, and consists, moreover, in the de- 

 velopment of a specific action of the nervous system which up to now 

 was observed only in man-produced, artificial conditions — hypnotism 

 of man and catalepsy of animals. Catalepsy in phasmids, the author 

 believes, is the first instance of normal^ regular, internally i^roduced 

 catalepsy in the animal hingdom. 



