ANATOMY AND PHYSIOLOGY. ie y eae 
horny palpi against its proboscis. The death-watch ~ 
beetle, like many other insects which produce the 
same kind of sound, merely knocks its head against 
a post. In all these cases, except the last, where the 
sound depends more on the wood than on the beetle, 
and where no special provision has been made to 
increase the sound, air cavities are placed in the im- 
mediate neighbourhood of the rubbing surfaces. 
Without such an arrangement the sound would 
scarcely be audible at all, and by increasing the size 
of the air-chamber, as by holding a buzzing fly or bee 
on a sounding board, the sound is made very much 
louder. By proper manipulation of the various parts, 
many of the sounds of attrition peculiar to the diffe- 
rent insects may be reproduced after their death. 
But I have never succeeded in thus reproducing those 
of the hornet or humble-bee. 
This class of insect musicians may be said to play 
on stringed instruments, on the harp or viol. The 
other class are fitted with wind instruments which 
‘approach most nearly to the principle of the accor- 
dion, or of the toy mouth-organ. Perhaps some 
persons, not used to finding jewels in a toad’s head, 
may prefer the comparison to that instrument of 
sound which is placed in the standing-board of all vo- 
cal toy-animals, from a lion to a lamb indiscriminately, 
whose note, so familiar to all who have little children, 
is produced by the sonorous vibrations of a membrane 
In acurrent of air. Foremost among those supplied 
with such spiracles we find the king: of insect-songsters 
the classical Cicada.* Then we have nearly the 
* It seems, by contrast with the mention of the cicada, quite an 
ungrateful task to be writing the history of wasps. The pleasant 
