THE OLFACTORY SENSE OF ORTHOPTERA 425 



The average reaction time of the males to the above six sources 

 of odors is 7 seconds, and of the females 9.7 seconds, making a 

 total average of 8.4 seconds for both sexes. The females were 

 less responsive to all the odors, except to that of the bran mash, 

 than were the males; but to bran mash each sex responded in 

 11 seconds. 



b. Grasshoppers with antennae severed through third segments. 

 These are the same insects used above; their antennae were cut 

 off and twenty-four hours later were again tested with the same 

 odors. As usual the females responded more slowly than did 

 the males, and the total average reaction time of both sexes is 

 9 seconds, whereas it was 8.4 seconds before they were mutilated. 

 They often tried to get at the bran mash and occasionally at the 

 oil of lemon when these substances were held under the cases 

 for a period of a minute or more. They were removed from the 

 cases to a large cage where they ate bran mash, drank water, 

 copulated, and lived just as long as did other individuals not 

 mutilated. 



Experiments with crickets (Gryllus pennsylvanicus) 



The preceding experiments were repeated by using the com- 

 mon black cricket. 



a. Unmutilated crickets. Since most of these ten insects failed 

 to respond to the dried leaves of pennyroyal and to the bran 

 mash, only the four essential oils were used as sources of odors. 

 The average reaction time of the males to these odors is 10 sec- 

 onds, and of the females 7.5 seconds, making a total average of 

 8.8 seconds. 



b. Crickets with antennae severed through third segments. The 

 antennae of the preceding crickets were cut off and two days 

 later these insects were again tested with the same odors. The 

 average reaction time of the males to the four odors is 7.5 seconds 

 and of the females 12.9 seconds, making a total average of 10.2 

 seconds. Confined in battery jars containing moist sand, these 

 mutilated crickets lived as long as others not mutilated; they 

 ate bread and pieces of apples; the males chirped, and the fe- 

 males oviposited eggs in the sand as usual. 



