AKTS PROBABLY HEAR HIGH NOTES. 227 



iso far as I am aware, by Dr. J. Braxton Hicks in his ex- 

 cellent paper on the ' Antennae of Insects,' published in 

 the 22nd volume of the 'Linnaean Transactions;' and, 

 again, by Dr. Forel in his 'Fourmis de la Suisse. 

 They certainly deserve more attention than they have 

 yet received. The cork-shaped organs (Figs. 6 and 7, e e) 

 occur in allied species; but these stethoscope-like 

 organs have not, so far as I am aware, been yet 

 observed in other insects. They consist of an outer 

 sac (Figs. 6 and 7, s), of a long tube (i), and a posterior 

 chamber {w\ to which is given a nerve {n). 



Forel • also describes these curious organs. He 

 appears to consider that the number varies consider- 

 ing. 6. 



Terminal portion of antenna of Myrmica ruginodis 5 x 76, 



ably, namely, from 5 to 12. My own impression is 

 that this difference is only apparent, and that in reality 

 the numbers in each species vary little. Though 



' Trans, of Linncpan Soc, vol. xxii. p. 391. 

 « Fmif"^ de la Svisne, p. 301. 



