94 ANIMAL AGGREGATIONS 



to coincide for a brief period. Fulton records that "when three or 

 more mutilated males were singing at once an utter confusion of 

 notes resulted, so that the rhythmical quality of their songs was 

 entirely obscured." The removal of the tibiae did not seem to affect 

 the general health of the insects. The loss of one or more legs ap- 

 pears to be a matter of relatively small importance among these 

 insects; they lived as long as did those with the ordinary quota of 

 legs. Similar observations were made by Fulton on a katydid and on 

 a grasshopper known as the "Nebraska conehead." 



Synchronic behavior may, of course, merely mean that the group, 

 while reacting as individuals, receive the stimulus at the same time 

 and so react simultaneously. This is illustrated by the responses 

 Minnich (1925) obtained when he exposed aggregations of caterpil- 

 lars to various sounds. Such synchronism has no bearing upon the 

 problem of group integration; but synchronism, such as described by 

 Fulton, of responses by members of the group to each other may well 

 have group significance. 



Buxton (1923) records an observation made some years before 

 upon the production of rhythmical sounds by termites. 'T noticed," 

 he says, "small numbers of winged termites emerging at one p.m. 

 from a subterranean nest under stones in a shady place by the road- 

 side. The ground round the mouth of the nest over a radius of three 

 feet was covered by thousands of small soldiers and a small number 

 of large soldiers. All of these were making a rhythmical sound which 

 resembled the noise made by sand falling on brown paper and which 

 was caused by tapping their heads on the dead leaves on which they 

 were standing. The sound was produced in perfect time at a rate of 

 about 48 beats per minute, and in the intervals between the beats 

 there was complete silence. This remarkable performance was not 

 disturbed by my collecting a considerable series of the performers, 

 but an hour later when I passed the spot, the emergence of 

 winged adults had ceased and not a soldier was to be seen above 

 ground." 



The termites were determined by Silvestri to be Acanthotennes 

 militaris Hag. Buxton does not believe that the rhythmical nature 

 of the sound production could be explained by substratal vibrations. 



