PSYCHE. 41 
which he succeeded in finding some obligue 
crystalline cones. 
Graber also describes an organ which 
he discovered in the antennae of several dip- 
tera, which he regards as auditory. This 
organ lies within the third antennal joint, on 
the inside and near the base. It is, briefly, 
a closed globular thick-walled, chitinous 
capsule, the wall being made up of rounded 
or oval plates, from each one of which 
springs interiorly a hair; a layer of epi- 
thelial cells surrounds the capsule, and out- 
side of this a tunica propria. A large 
nerve branch runs to this organ, but the 
intimate connection between the elements 
of the two could not be made out. Graber 
thinks, as will be supposed, that the hairs 
vibrate to sound waves, and he sees noth- 
ing to indicate that the organ may be other 
than auditory. The ordinary hairs cloth- 
ing the antennae, Graber shows, are in 
connection with special nerve elements, and 
are probably organs of touch. 
Another singular organ Graber finds © 
in an unknown dipterous larva, and this, 
too, as it can apparently be nothing else, is 
thought auditory. It is situated under the 
dorsal integument, from which it is quite 
independent, at the junction of the ninth 
and tenth segments, and just behind the 
dorsal vessel. It consists of a pear-shaped 
sac, prolonged backwards into a fine tube, 
the end of which, lying in the terminal seg- 
ment, unfortunately could not be demon- 
strated ; but Graber thinks the sac and its 
tube represent an infolding of the integu- 
ment. ‘I'wo diverging muscles inserted on 
the sides of the eighth segment support the 
59 Arch. Mikr. Anat., v. 16, p. 36. Abstract, 
Journ. Roy. Micr. Soc., v. 2, p. 45. 
60 Tbid., p. 47. 
61 Carus’ Zool. Anzeig., v. 2, p. 229. 
forward end, the sac being thus suspended 
by two anterior and one posterior (the 
tube) braces. Within the sae are eight 
black rounded bodies, borne on short stalks, 
and looking like so many berries. These 
bodies — the presumed otoliths — are hung 
in four pairs, one behind the other, thus giv- 
ing a segmented character to the organ, 
which is still more apparent from the fact 
that the second pair, and the third and 
fourth — which are united together — lie 
in separate sacs within the first, like the 
coats of an onion. The organ is supplied 
with a nerve on each side, but nothing 
more definite could be shown. As to this 
larva, Dr. Hermann Krauss ® states that it 
is the larva of Tabanus autumnalis L., and 
that Prof. Brauer pointed out the organ in 
question to his classes four years ago. 
Krauss affirms that it is o be found in 
the perfect insect, by the study of which its 
nature can perhaps be settled. 
With regard to the supposed antennal 
otocysts of Graber, Dr. Paul Mayer in a 
letter to Carus’ Zool. Anzeiger (v. 2, p. 
182), states that these are by no means 
closed vescicles but are really wide-open 
mouthed sacs. Moreover that though only 
one is present in Syphus and Drosophila, 
Sicus has at least three, and Eristalis a 
whole series, of them. Indeed, Mayer 
thinks the size of the third antennal joint 
stands in direct relation to the number of 
these organs borne on it. Musca vomitoria 
has nearly fifty, for example, which in this 
case have been described and figured by 
Leydig,” so that Graber cannot claim them 
as his discovery. Mayer believes them 
62 Miiller’s Arch., 1860, p. 276, pl. 8. They are 
also described in Mr. Lowne’s monograph on the 
Blow-fly, London, 1870. This writer believes 
them olfactory organs. 
