176 THE ENTOMOLOGIST. 



in localities as widely separated as Panama and Costa Eica in 

 Central America, and in the islands of Grenada and Trinidad in 

 the West Indies, but always, and only, on this one species of 

 aphid. 



It has been suggested to me that the movements are pro- 

 tective and designed to ward off parasites, and in this connection 

 it should be noted that on one occasion I observed that the 

 aphids on a leaf that I had not touched were moving rhythmi- 

 cally, and further search disclosed the presence of two syrphid 

 fly grubs moving among them and feeding on the colony. It 

 must also be recollected that the sound, if deliberate, may be 

 awe-inspiring to some small enemy although almost inaudible to 

 our ears. 



This whole question of synchronised actions needs much 

 more investigation before a complete understanding is likely to 

 be found. At the same time, it seems likely from the above 

 that we are dealing with extremely rapid responses of a large 

 number of individuals to a single impulse or stimulus. In the 

 case of the fire-flies recorded by Hess this seems the obvious 

 explanation, and in most of the other cases it could also be 

 applied. All the above insects, and many others, normally 

 produce rhythmic actions as individuals, and when large numbers 

 are within range of an original stimulus, the synchronising of 

 the rhythm is natural. In the case where each individual gets 

 its stimulus from the one next to it we would expect a more or 

 less rapid wave from one end of the association to the other. 

 Something of this nature was seen by Hess. 



The case of the aphids shows that if two sets of rhythm are 



in progress at the same time, some individuals will respond to 



one and some to the other, but none are able to respond to the 



stimulus from the other section which takes place between their 



own pulsations and outside their rhythm. 



Cairo ; 



June 9th, 1922. 



A NEW FOSSIL LONGICORN BEETLE. 



By T. D. A. Cockekell. 



Last year, when at Cambridge University, I was kindly per- 

 mitted by Prof. Marr to study a collection of Miocene fossils 

 from the famous locality at GEningen in Baden. I wrote a paper 

 on certain fossil beetles in the collection, and sent it to the 

 ' Canadian Entomologist.' Through some mischance it never 

 reached the Editor's hands, and unfortunately the figures are 

 lost and cannot be replaced. There was, however, one very 

 fine new longicorn (Prioninse), which should be made known. 



