1914.] NATURAL SCIENCES OF PHILADELPHIA. 309 



males may be due, however, to the fact that these males were young 

 and because they were not very active. The olfactory sense of the 

 males of Formica and of Camponotus seems to be about equally devel- 

 oped in both. The olfactory sense in the males of Camponotus seems 

 to be more highly developed than it is in the workers of the same 

 genus. There seems to be practically no difference in the ability 

 of the large and small workers of Camponotus to receive odor stimuli. 



Ants with the funiculi either cut off or covered with glue are not 

 normal and they do not live long. They soon become inactive and 

 some of them can hardly be mechanically irritated. Those which 

 almost fail to respond to mechanical stimuli never respond to odor 

 stimuli. These were discarded from the experiments in which 

 odors were used and all the others were tested with odors. The 

 average reaction times of the mutilated ants are about double those 

 of unmutilated sisters. The slowness in responding to odors is 

 probably due to the inactiveness of the mutilated insects. If the 

 slow reaction times indicate that some of the olfactory organs were 

 prevented from receiving odor stimuli, then the olfactory organs 

 that brought about the responses must be looked lor elsewhere than 

 on the antennae. 



Hornets with the antennae cut off are not normal and never live 

 long. The reaction time of hornets thus mutilated is only 0.66 

 second more than that of unmutilated hornets. Most of the olfac- 

 tory organs, if not all, of hornets must be looked for elsewhere than 

 on the antennae. 



IV. Morphology of the Olfactory Pores. 



Since the organs in the antennae of ants and hornets fail to receive 

 most, if not all, of the odor stimuli used in the preceding experiments, 

 and because the writer proved experimentally that the pores first 

 described by Hicks (1857) do receive odor stimuli in the honey bee, 

 these pores in ants and hornets will now be discussed. 



1. Disposition. 



In making a study of the disposition of the olfactory pores of ants 

 and hornets the following were used: five specimens each of winged 

 females, winged males, and major workers of Formica; five specimens 

 each of dealated females, winged males, major and minor workers 

 of Camponotus; and one specimen of Vespula maculata. All the 

 wings and legs of all 36 specimens were examined carefully for pores. 

 Since the winged female of Formica is typical, its olfactory pores 



