DIPTERA — HYMENOPTERA. 69 



Landois mentions that he has heard species of 

 Eristah's and Syrphus sing while they have been 

 sitting quietly. The dragon-flies (Libellulina) also 

 produce a sound by means of their spiracles. 



Among Hymenoptera, the hum of an angry bee is 

 proverbial. Nor must I omit to mention the piping 

 noise made by young queen bees. It is well known 

 that there is only one queen in a hive, and that 

 working bees never turn their back on her; as she 

 moves among the combs, they all turn towards her. 

 If there has been a swarm led by the old queen, the 

 young queen who has succeeded often makes a piping 

 noise, first noticed by Huber, whose statements are 

 generally recognized as correct.* While "singing" 

 the queen assumes a particular attitude, and the other 

 bees all lower their heads and remain motionless until 

 she begins to move again. In the mean while, if there 

 are any other young queens which have not yet left 

 the cells, they answer the old one, and their notes seem 

 to be sounds of challenge and defiance. 



Other bees also produce a sound by means of their 

 spiracles quite different from the humming of their 

 wings. Mutilla Europsea, a wingless species, related to 

 and not unlike the ants, makes, when alarmed, a rather 

 sharp noise by rubbing one of the abdominal rings 

 against the other. 



Under these circumstances, Landois asked himself 

 whether other genera allied to Mutilla might not 

 possess a similar organ, and also have the power of 

 producing sound. He first examined the genus Ponera, 

 which, in the structure of its abdomen, nearly resembles 



* Huber, '* Obs. sur les Abeilles ; " Bcvan, " On the Honey Bee ; " 

 Langstroth, " On the Honey Bee." 



