68 Annals Entomological Society of America [Vol. XII, 



except the army worms, had the habit of crawHng into the 

 corners and lying there more or less dormant and in such a 

 position would never respond to odors; therefore, before testing 

 a larva it was first necessary to see that it was lying flat on the 

 bottom of the case, and in order to insure, if possible, a response 

 to another odor after an interval of 15 minutes, it was usually 

 touched with a pencil to "awaken it from its stupor." Caterpil- 

 lars in their webs rarely responded to the odors used. The fol- 

 lowing records include only the first responses and their reaction 

 times. 



Medium Sized Tent Caterpillars {MaJacosoma americana Fab.). 



Oil of peppermint: 



6 moved head slightly. 1 raised head and crawled away. 



1 moved away slowly. 1 moved head and worked mouth parts. 



1 raised head quickly. 



Reaction time 3 to 15 seconds, average 7.5 seconds. 



Oil of thyme: 



6 moved head slightly. 1 raised head and moved away slowly. 



3 moved away slowly. 



Reaction time 3 to 15 seconds, average 5.4 seconds. 



Oil of wintergreen: 



5 moved head slightly. 2 raised head and moved away slowly. 



2 showed no response. 1 moved away slowly. 



Reaction time 4 to 60 seconds, average 20.6 seconds. In all cases 60 

 seconds was regarded totally negative. 



Dried leaves of pennyroyal: 



5 moved away slowly. 1 moved head sidewise. 



3 moved head slightly. 1 showed no response. 



Reaction time 3 to 60 seconds, average 22.2 seconds. 



Dried leaves of spearmint (odor very weak): 



5 showed no response. 2 moved head slightly. 



2 moved away slowly. 1 moved leg back and forth. 



Reaction time 5 to 60 seconds, average 38.3 seconds. 



Wild cherry tree leaves cut into small pieces (their favorite food): 



4 showed no response. 1 moved away slowly. 



4 moved head slightly. 1 raised head slowly. 



Reaction time 5 to 60 seconds, average 42.5 seconds. 



Old honey and comb (odor very faint): 



6 showed no response. 4 moved head slightly. 



Reaction time 20 to 60 seconds, average 51.5 seconds. 



Empty and odorless vial (used as a control): 

 id showed no response. 



Small Fall Webworms {Hyphanlria cunea Dru.) 



Oil of peppermint: 



3 moved slightly. 1 moved head sidewise. 

 2 raised head and thorax quickly. 1 turned around. 



2 worked mouth parts. 1 raised head. 



Reaction time 2 to 40 seconds, average 11.8 seconds. 



