SIE JOHN LUBBOCK ON ANTS, BEE8, AND WASPS. 623 



greater mobility to the sting, might have been an advantage, and 

 thus gradually produced in certain cases, without necessarily 

 being developed in others, in which, perhaps, some other advantage 

 was enjoyed. 



, The so-called stingless ants, as Forel and Dewitz * have 

 clearly shown, possess in reality a rudimentary sting ; and their 

 ancestors obviously had a more developed one. Such cases, 

 therefore, as Pheidole and Atta, to which M. Porel refers, repre- 

 sent cases in which, perhaps with reference to the powerful de- 

 velopment of the mandibles, the sting has fallen partly into disuse, 

 and consequently has diminished in size. On the other hand, the 

 second knot having once been formed, has retained its existence. 

 It will be observed also that the "knot" in the Formicidse, 

 where it is single, is much more elevated than in the Myrmicidse 

 where there are two knots, and consequently two sets of muscles 

 moving the abdomen. Thus, while the Myrmicidse have two sets 

 of muscles acting on the abdomen, and the Pormicidse only one, 

 the difference is to a certain extent neutralized by the fact that 

 the muscles in the latter family are longer than in the MyrmicidaB. 

 This accounts I think, for the elevation of the knot or scale in 

 Formica and the allied genera. 



As to Sounds emitted hy Ants. 



In ' Nature ' for December is a letter from Mr. T. S. Tait, 

 who, writing from Baroda, says that by means of the microphone 

 " we have been able to hear the roar of a black ant when attacked 

 by its companion." It is unfortunate that Mr. Tait does not 

 mention the species, because some of the Mutillidse make a sound 

 which is audible even to the naked ear. Moreover the expres- 

 sion " attacked by its companion " is curious, and does not 

 harmonize with the usual habits of ants. Still I am quite dis- 

 posed to believe that ants do produce sounds. 



In the previous paper I have mentioned that I was never able 

 to satisfy myself that my ants heard any sounds which I could 

 produce. On the other hand, I have tried unsuccessfully various 

 experiments, in order to ascertain whether the ants themselves 

 produced any sounds for the purpose of conveying signs or ideas. 

 Prof Tyndall was good enough to arrange for me one of his sen- 

 sitive flames ; but I could not perceive that it responded in any 

 * Zeit. f. wiss. Zool. vol. xxviii. 



LINN. JOTJEN. — ZOOLOGY, VOL. XIV. 47 



