ANTS PROBABLY HEAR HIGH NOTES. 227 
so far as I am aware, by Dr. J. Braxton Hicks in his ex- 
cellent paper on the ‘ Antenne of Insects, published in 
the 22nd volume of the ‘Linnean 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, ee) 
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 (¢), and a posterior 
chamber (w), to which is given a nerve (7). 
Forel! also describes these curious organs. He 
appears to consider that the number varies consider- 
Fig. 6. 
Terminal portion of antennz of Myrmica ruginodis 3 x 75. 
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 
1 Trans. of Linnean Soc., vol. xxii. p. 391. 
2 Fourmis de la Suisse, p. 301. 
