THE HARVESTING-ANTS OF FLORIDA. 93 



with their lives, and no doubt would have 

 succeeded had it been any ordinary foe. 



This phenomenon the soldiers and queens 

 with smooth mandibles is very puzzling, 

 and has excited much interest among natu- 

 ralists both in this country and in Europe. 

 I sent specimens to Mr. Charles Darwin, 

 which he forwarded to Mr. Frederick Smith 

 of the British Museum (who, Mr. Darwin in- 

 forms me, is the highest authority in Europe 

 on ants and other Hymenoptera). Mr. Smith 

 says : " Your observations on the structural 

 differences in the mandibles of this ant are 

 quite new to me." I also sent specimens to 

 the eminent naturalist, Dr. Auguste Forel of 

 Munich, who, like Mr. Smith, had never ob- 

 served this feature of the mandibles in any 

 ant ; but he has a theory to account for it 

 that the smooth mandibles have been worn 

 down by labor. If this theory is true, how 

 can we account for the fact that other ants 

 do not wear down their teeth ? The chiti- 

 nous covering of this harvesting-ant is firm 

 and hard. The stage forceps of my micro- 

 scope closes with a spring ; and in studying 

 this ant I have put thousands of individuals 

 to the test, holding them in the forceps to 

 examine their mandibles ; and in no instance 

 do I recollect seeing one injured, while many 



