444 N. E. MCINDOO. 



which is only one-half as rapid as the reaction time of the same 

 species devoid of antennae. Three failed to respond to the oil 

 of peppermint, one to the oil of thyme and two to the oil of 

 wintergreen. A common response was to vibrate the legs. They 

 were placed into the cage with the other species of blister beetles. 

 They were regularly provided with a fresh supply of goldenrod. 

 In the cage they appeared normal, and they copulated as much 

 as usual. They lived from 2 to 25 days with 11.2 days as an 

 average. 



(a) Effects with AntenncB Pulled Off. 



The antennae of 30 Epicauta pennsylvanica were pulled off at 

 their bases. When tested with the odors from the essential oils 

 three days later, the 22 remaining live beetles gave a general 

 reaction time of 5.3 seconds. They were only slightly abnormal 

 in behavior. They lived from 2 to 25 days with 8.7 days as an 

 average. 



(&) Effects with Elytra and Wings Pulled Off. 

 The elytra and wings of 21 Epicauta pennsylvanica were pulled 

 off at their articulations. A small drop of blood exuded from 

 each wound. Blood was also seen in the distal ends of the elytra. 

 When tested with the odors from the essential oils two days later, 

 the 17 remaining live beetles gave a general reaction time of nine 

 seconds. One of them failed to respond to the oils of thyme and 

 wintergreen. These insects appeared normal in confinement 

 with the other blister beetles. They copulated as usual. They 

 lived from i to 33 days with 10.7 days as an average. 



A summary of all the preceding experiments to determine the 

 location of the olfactory organs in beetles is best presented in a 

 tabulated form. The following table is such a summary. Since 

 a comparison of the behavior of unmutilated and mutilated in- 

 sects alone is not always a safe criterion for judging the general 

 behavior of mutilated beetles, the behavoir of the mutilated 

 beetles recorded in this table is based mostly upon a comparison 

 of the longevities of unmutilated and mutilated individuals of 

 the same species. A " + " after a figure in the last column means 

 that all the insects used in the experiment have not yet died. 

 The longevity is based only on those that have died up to the 

 time of this writing (Jan. 15). 



