722 
RHYNCHOTA. 
sexes and not, as in some groups, in the males alone. Among moths, our 
common death’s head ( Acherontia styx , Westw.) produces a sound by 
the friction of the palpi and the proboscis. This is stated to occur also 
in other species. A Sphingid larva common in the hills also produces 
a hissing sound on being touched ; this is probably protective, just as 
the bizarre spots on these larvae are. 
Shipley and Wilson have described a sound-producing organ which 
is found on the wing of the mosquito Anopheles maculipennis , Meig. At 
the base of the wing is a movable bar bearing teeth, which engage 
against ridges on another slightly movable bar ; the vibration of the 
wing produces movement of the teeth against the ridges, causing rapid 
vibration ; the note is ordinarily constant in pitch but rises as the wing 
is shortened. (Trans. Roy. Soc. Edin. XL, pt. 11, No. 13, 1902.) 
Lowne states that the common blowfly, as some other Diptera, 
emits sound through the large thoracic spiracles. Amongst Hemiptera, 
besides the stridulation of Tessaratoma papillosa, Thunb., we find 
that certain Reduviids can emit sounds ; Corixa emits musical chirps, 
produced by the friction of the forelegs on the beak. 
Finally the Cicadas are notorious for their voices, the males singing 
constantly. Their song is produced by a tense membrane to which is 
attached a muscle, which throws the membrane into vibration ; the vi¬ 
brations are intensified by other resonant membranes and by the leaf¬ 
like lobes on the ventral surface. It is said that the peculiar diminu¬ 
tion and intensification of the sound heard in some South Indian species 
(and which is exactly like that of the watchman’s wooden rattle used at 
the boatraces at Cambridge) is produced by the opening and closing 
of the aperture at the base of the abdomen. 
Finally we may remark that it is probable that many insects produce 
sounds unheard by us, since our ear will not record vibrations of more 
than a definite rapidity. Observations on a number of insects have 
shown that in some cases there are auditory organs m species whose song 
has not been heard, and that in others the movement necessary to 
produce song can be perceived but no sound is heard. This is the case 
with one of our common crickets ; we have frequently seen its wings in 
vibration in a similar manner to that of Brachytrypes achatinus, but we 
can only hear the sound produced by the latter. It is possible that 
investigation of the anatomy of insects will reveal auditory and sound- 
producing apparatus in a greater number than are at present known. 
Fulgorid^e. 
Ocelli usually two , placed in cavities beneath the eyes ; antennae 
of two joints and a bristle, placed beneath the eyes. 
This is the largest, if not the most important, family of Homoptera 
occurring in the plains and it includes a considerable variety of forms. 
A number are large brightly coloured moth-like forms which fly by day 
