THE SEXSATIOXS OF AXTS. 513 



sound waves from a piano, violin and Galton whistle, which collectively 

 gave a range of from 27 to 60,000 vibrations per second." The insects 

 reacted, however, to vibrations reaching them through the soil and 

 other solids. These vibrations were received through the legs, as they 

 were perceived even when the antennae, head, abdomen and any one or 

 two pairs of legs were removed. In contradiction to this view and 

 that of Forel, several authors have recently maintained that ants do 

 perceive aerial vibrations. That this is the case has been stated by 

 Weld (1899) for Crcniastogastcr lincolata, Las-ins aincricaints and 

 Aphccnogastcr sp., and by Metcalf (1900) for "a small black ant." 

 Wasmann (i8gif, 1899*7) has recorded similar, rather inconclusive 

 observations. I have also virtually expressed myself in favor of such 

 a view in one of my papers (19030), in a passage which as been over- 

 looked or misunderstood by some recent students of this subject, and 

 may therefore be repeated in this place : " Stridulation, at least among 

 the Myrmicinse, Ponerinae and Dorylinae, is an important means of com- 

 munication, which Bethe has completely ignored and even Forel and 

 other myrmecologists have failed to appreciate. It readily explains the 

 rapid congregation of ants (Myrmicinse) on any particle of food which 

 one of their number may have found, for the excitement of finding 

 food almost invariably causes an ant to stridulate and thus attract other 

 ants in the vicinity. It also explains the rapid spread of a desire to 

 defend the colony when the nest is disturbed. This is especially notice- 

 able in species of Pheidole, J\Iyniiica and Pogoiwinynnc.v. It is the 

 secret of being able in a short time to catch ants like P. inolefaciens 

 in great numbers by simply burying a wide-mouthed bottle up to its 

 neck in the mound of the nest. An ant approaches and falls into the 

 bottle. It endeavors to get out, and failing, begins to stridulate. This 

 at once attracts other ants which hurry over the rim and forthwith 

 swell the stridulatory chorus till it is audible even to the human ear. 

 More ants are attracted and soon the bottle is filled. If it be corked 

 and shaken for the purpose of still further exciting its contents, and 

 then held over another Pogonomyrtnex colony whose members are 

 peacefully sauntering about on the dome of the nest, the wildest excite- 

 ment will suddenly prevail, as if there had been a call to arms or to 

 dinner. Even more remarkable is the Stridulation in a colony of Atta 

 ferz'cns (=^tc.\'ana), the Texan leaf-cutting ant. Here the different 

 ants, from the huge females through the males, large soldiers and 

 diminishing castes of w r orkers to the tiny minims, present a sliding 

 scale of audibility. The rasping Stridulation of the queen can be heard 

 when the insect is held a foot or more from the ear. To be audible 

 the male and soldier must be held somewhat closer, the largest workers 

 34 



