212, Dr. David Sharp on 
results ; and this independently of any differences in the 
muscular apparatus, which may be considerable or not, 
this point not having been at all examined. 
It is impossible to examine a series of these structures, 
to note their peculiarities and the perfection that is 
attained in some of them, without concluding that they 
must be of considerable importance in the organisation 
of the creature. Whether they form a definite means of 
communication I cannot even guess, though I can quite 
see that investigation might probably prove them to be 
capable of producing a considerable variety of sounds in 
the case of one of the higher species. 
It is true, as I have already stated, that these organs 
of stridulation do not exist in the great division Formi- 
cides of the older authors (the Camponotides and Doli- 
choderides of Forel); but nevertheless it appears quite 
possible that the same parts in those insects may be 
able to produce a considerable variety of sounds of a 
rustling nature by rubbing together, with a variety of 
movement, the sculptured surfaces of two overlapping 
parts, or by dragging a semimembranous border over a 
wrinkled surface; and the examination of Camponotus 
cruentatus seems to increase the probability of this sup- 
position. 
The striation of the file in ants is similar to what it is 
in such Coleoptera as the Longicornia and Ipsini, though 
it is finer and more delicate iu the ants. In this latter 
group the delicacy of movement given to the parts of the 
stridulating apparatus by the perfection of the joints at 
the nodes greatly increase the probability that a con- 
siderable variety in the sound may be produced. The fact 
that in Sima, sp. the band is divided abruptly into two 
very different parts strongly supports the idea that 
variety in the sound is of importance, as well as the 
mere making of a noise. 
Perhaps I may be allowed to remark in concluding 
that I consider organs of hearing in insects and the 
sounds produced by the creatures to be a more promising 
field of research than the organs of sight, owing to its 
greater simplicity. If we could invent some means of 
hearing the sounds produced by ants, it might do much 
towards solving the question of their means of communi- 
cation and recognition. I may, too, say a word of 
caution against the supposition that ‘‘ hearing” in ants 
e 
