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Acanthia lectularia 
appearance suggesting that the cavity is filled with fluid. His experi¬ 
ments with bugs have never yielded the oil drop from the central pore 
under the meta-thorax which Landois says can be seen. 
There seems to be a peculiarity about the olfactory organ which the 
writer mentions with some reserve. When seen in section it is easily 
recognised, and is large enough to extend over a number of the sections, 
and since the ampullae stain deeply it is very noticeable, whether the 
section is transverse or longitudinal. When the bug is mounted whole 
in balsam it is also very distinct if seen at all. In his series of sections 
some show absolutely no trace of it, and this is not due to tearing of the 
section, for even if torn, the organ can easily be recognised although 
its position may be changed. A possible explanation which suggests 
itself is that the organ (which is common to both sexes) may become 
hypertrophied at times of sexual activity, and at other times be so small 
as to be practically invisible. As the scent of insects at such periods is 
much stronger than usual it may well be that in the bug a keener sense 
of smell may then also develop. 
Landois asserts that the scent apparatus consists of : 
(1) The gland, 
(2) The bladders (for storage), 
(3) The exit 
(Plate XXII, fig. 2). 
He describes as the scent gland the organ which, from its structure, 
the writer considers to be the olfactory organ; while what are in reality 
the scent glands Landois calls the storage bladders. The position he 
assigns to the “ gland ” (olfactory organ) as shown in his figure is 
cpiite wrong, as it is in the middle line, and, as already said, it is enclosed 
in the passage connecting the two glands (“ reservoirs ” according to 
Landois). 
When discussing the exit he says : “ Die Ausflussoffnung des Stink- 
sackes befindet sich zwischen der Insertion des zweiten und dritten 
Beinpaares ” (page 219, lines 12, 13)—while further on he says : “ Die 
Oeffnung liegt jedoch versteckt und zwar unter jener Platte, welche 
ahnlich einem Processus xiphoideus vom Mesothorax her zwischen die 
Hinterbeine sich einscheibt ” (page 221, lines 19-22). 
It is thus difficult to understand what he actually means. In his 
figure he shows the opening of the glands as in the middle line 
(Plate XXII, fig. 2). 
Figure 13 shows the scent and olfactory apparatus as seen by the 
writer. 
