70 Annals Entomological Society of America [Vol. XII, 



Oi! of wintergreen: 



5 raised head quickly and moved 2 raised head slowly. 



it sidewise. 1 raised head quickly. 



2 raised head quickly and moved 



backward. 



Reaction time 2 to 10 seconds, average 2.9 seconds. 



Dried leaves of pennyroyal: 



8 raised head slowly. 1 moved away slowly. 



1 raised head quickly. 



Reaction time 2 to 10 seconds, average 4.2 seconds. 



Dried leaves of spearmint (odor very weak) : 



6 raised head slowly. 1 raised head slowly and waved it 



3 raised head quickly. sidewise. 

 Reaction time 2 to 4 seconds, average 2.7 seconds. 



Fresh grass in vial (food of these larvae): 



2 raised head slowly. 2 moved backward slowly. 

 2 moved slightly. 1 moved forward quickly. 



2 showed no response. 1 raised head and bit screen-wire bottom 



of case. 

 Reaction time 2 to 60 seconds, average 19.1 seconds. 



Butterfly L.\rv.\e (Papilio polyxenes Fab.) 



Oil of peppermint: 



5 raised head. 5 showed no response. 



Reaction time 3 to 60 seconds, average 33.2 seconds. 



Oil of thyme: 



5 raised head. 2 showed no response. 



2 moved quickly. 1 moved caudal end of body. 



Reaction time 2 to 60 seconds, average 22.1 seconds. 



Oil of wintergreen: 



5 moved slightly. 5 showed no response. 



Reaction time 7 to 60 seconds, average 40.7 seconds. 



Dried leaves of pennyroyal: 



4 showed no response. 3 moved slightly. 



3 raised head. 



Reaction time 10 to 00 seconds, average 43.5 seconds. 



Dried leaves of spearmint (odor very weak): 



5 showed no response. 2 moved slightly. 

 3 raised head. 



Reaction time 3 to 60 seconds, average 37.3 seconds. 



In comparing the preceding reaction times, no conclusion 

 can be drawn in regard to the comparative sensitiveness of the 

 five species tested, because the responses depended more on the 

 behavior of the larva tested than on its ability to perceive 

 chemical stimuli. Of the five species used, only the army 

 worms were favorable for experimental purposes; these were 

 usually active, never failed to respond when tested, and the 

 responses were generally quick and pronounced ones. Of the 

 five species used, the butterfly larvae were the most sluggish 

 and their reaction times are the slowest of all. 



