The Psychology of ''Playing 'Possum" 47 



long, which swims gracefully. As soon as a water beetle 

 appears, it hangs in the water as limp as a cotton thread. 



Most students of vertebrate behavior are familiar with 

 the behavior of the black viper, which Weir considers the 

 greatest letisimulator of all animals. When it is threat- 

 ened and a mode of escape is not apparent, the snake 

 writhes and twists in apparent agony, then turns over on 

 its back and seems to be in rigor mortis. You seem to 

 see the reptile pass through its death throes and expire. 

 Turn your back a few moments and the snake disappears. 



The opossum and the black viper seem to have made a 

 lasting impression on Weir, for, while citing examples 

 from the protozoa, worms, insects, reptiles, birds and 

 mammals, he leaves the impression that the most remark- 

 able examples of death-feigning are to be found in the 

 reptiles and certain mammals. Since that time much 

 attention has been given to the study of the letisimula- 

 tion of insects. Barret (Porto Rico Agri. Exp. Sta. Bull., 

 1902) has studied it in the mole-cricket; Gee and Lathrop 

 (Ann. Ent. Soc. of Amer., 1912, Vol. V., pp. 391-399) and 

 Johnson and Girault (Circ, Bull, of Entom., U. S. Etept. 

 of Agri.), in the plum cuculio; Gdrault (Entom. News, 

 1913, Vol. XXaV, pp. 338-344), in trox; Holmes (Jour, 

 of Comp. Neur. & Psy., 1906, Vol. XV, pp. 305-349), in 

 the water scorpions; Newell (Jour, of Ec. Ent., 1913, Vol. 

 VI, pp. 55-61), and Weiss (Canad. Entom., 1913, Vol. 

 XiLV, pp. 135-137) in the rice weevil; Riley (Ann. Ent. 

 Soc. of Amer., 1912, Vol. V, pp. 273-292) in dragon fly 

 nymphs; the Severins (Jour. N. Y. Entom. Soc, 1911, 

 Vol. XIX, pp. 99-108), in the giant water bugs, and Wod- 

 sedalek (Ann. Entom. Soc. of Amer., 1912, Vol V, pp. 

 31-40, 367-381), in May-fly nymphs and dermestid larvae. 

 In the light of the remarkable traits revealed by these 

 investigators, were he writing his article today. Weir, 



