156 



HYMENOPTERA 



by striking the leaf with its head in a series of spasmodic taps. 

 The same observer has recorded a still more interesting fact in 

 the case of another species of this genus — a large brown ant — 

 found in Sumatra. The individuals were " spread over a space, 

 perhaps a couple of yards in diameter, on the stem, leaves, and 

 branches of a great tree which had fallen, and not within sight 



of each other ; yet the tapping was 

 set up at the same moment, con- 

 tinued exactly the same space of 

 time, and stopped at the same in- 

 stant ; after the lapse of a few 

 seconds all recommenced at the 

 same instant. The interval was 

 always of about the same duration, 

 though I did not time it ; 

 each ant did not, however, beat 

 synchronously with every other 

 in the congeries nearest to me ; 

 there were independent tappings, 

 so that a sort of tune was played, 

 each congeries dotting out its 

 own music, yet the beginnings 

 and endings of the musical parties 

 were strictly synchronous." 

 Mr. Peal has also recorded that an ant — the name is not 

 mentioned, but it may be presumed to be an Assamese species — 

 makes a concerted noise loud enough to be heard by a human 

 being at twenty or thirty feet distance, the sound being produced 

 by each ant scraping the horny apex of the abdomen three times 

 in rapid succession on the dry, crisp leaves of which the nest is 

 usually composed. These records suggest that these foliage-ants 

 keep up a connection between the members of different nests 

 somewhat after the same fashion as do so many of the terrestrial 

 Camponotides. Although the species of Camponotides have no 

 special organ for the production of sound in the position in which 

 one is found in Myrmicides and Ponerides, yet it is probable that 

 they are able to produce a sound by rubbing together other parts 

 of the abdomen. 



Fig. 65. — Polyrhachis pandurus, 

 worker. Singapore. 



