114 Psyche [June 



not again seen. It is certain, therefore, that it must be very rare 

 and local. Since the various species of Hetcerius occur only with 

 species of Form ica or very rarely ( H. minimus Fall) with species of 

 Lasius, the occurrence of Melanetcprius in the colonies of a 

 Myrmicine ant is additional evidence, if it were needed, that Fall 

 was right in regarding this beetle as the type of a distinct genus 

 and not as an aberrant species of Hetcerius. 



THE SOUND-MAKING OF DIPTERA AND 

 HYMENOPTERA. 



By C. E. Pemberton, 

 Stanford University, California. 



That many Diptera and Hymenoptera produce sounds in two 

 distinct ways has been an accepted belief for a long time. One 

 of these ways is by the rapid vibration of the wings in the air; the 

 other one is by the forcible inspiration and expiration of air 

 through the spiracles, especially the thoracic ones. 



The production of insect sounds by organs other than the wings 

 was probably first noted by Aristotle when he said that the 

 tracheae were set in vibration by rapid in- and out-rushings of air 

 causing a vibration somewhat similar to that produced by certain 

 reed instruments. 



Dr. H. Landois in 1867 in a very complete and exhaustive paper 

 on the sounds and sound apparatus of insects devoted consider- 

 able attention to the Diptera and Hymenoptera. He made some 

 elaborate explanations to prove that sounds were produced by 

 certain vibratory portions of the spiracles, and performed a number 

 of experiments to verify his explanations. 



Burmeister also has advanced the theory that flies produced 

 sounds by forcing air violently through the spiracles thus pro- 

 ducing a vibration loud enough to be heard, and similar theories 

 have been advanced by others. Landois 's work however is still 

 probably the standard. 



Landois experimented with the house fly, {Musca domestica) a 

 flower fly {Eristalis teriax), a dung fly {Scatophaga stercoraria). 



