214 



JOSEPHINE ALBERTA WILLIS. 



Some idea of the striking characteristics of the movements of 

 the grasshoppers produced during and after they are under the 

 influence of carbon dioxide, may be derived from the following 

 paragraph . 



i 

 - 



c 



~ 



r20 



10 





5C 



minutes exposed 



FIG. 2. Abscissa: Length in minutes of exposure to the gas. Ordinates at left, 

 rate p. min. exposure. At right, time in minutes. 



Curve A = Time in minutes to the first movement. 



Curve B = Time in minutes to the recovery. 



Curve A' = Rate of first movement per minute exposure. 



Curve B' = Rate of the recovery per minute exposure. 

 (For further description see text.) 



When an animal is subjected to the gas, it undergoes violent 

 reflexes in all appendages at times, the abdomen, due to 

 stimulated respiratory movements, curls and uncurls; however, 

 some animals make no movements. The period before asphyxia- 

 tion occurs is less than one minute, usually about twenty to thirty 

 seconds. After asphyxiation the animal becomes stiff or limp, 

 depending upon the individual, and apparently lifeless, although 

 some may exhibit slight reflexes. They remain in this condition 

 until removed from the gas. In longer exposures some animals 

 secrete an excessive amount of saliva and the antenna; droop. 

 The salivary secretion may occur at any stage or upon removal 

 from the gas. The first movements after removal from the gas 



