We may make our first acquaintance with these insects by keeping some
specimens in confinement. A tin box, with a glass lid, will make a
capital dwelling for them. Some paper should be put in, for them
to hide in away from the light, and there can be no difficulty in
providing them with food. ‘Bark, leaves, the pith of living cycads,
paper, woollen clothes, sugar, cheese, bread, blacking, oil, lemons,
ink, flesh, fish, leather, the dead bodies of other cockroaches,
their own cast skins and empty egg-capsules, all are greedily
consumed. Cucumbers, too, they will eat, though it disagrees with them
horribly[16].’
We have Dr. Sharp’s authority for the statement that in confinement
these insects are rather amusing pets, as they ‘occasionally assume
most comical attitudes, especially when cleaning their limbs. This they
do somewhat after the fashion of cats, extending the head as far as
they can in the desired direction, and then passing a leg or an antenna
through the mouth; or they comb other parts of the body with the spines
on the legs, sometimes twisting and distorting themselves considerably
in order to reach some not very accessible part of the body[17].’
The prejudice against these insects is, however, so strong, that most
people will prefer to examine dead rather than living specimens, on
account of the disagreeable odour of the latter. This odour is due to
a fetid excretion from the mouth, and if the specimens are killed by
dropping them into boiling water, this will be discharged, and after a
little while they may be taken out with a pair of forceps, and put into
spirit for preservation. If they are dropped alive into spirit, the
excretion will communicate its strong scent to the preserving medium,
and this should be changed before the insects are examined.
From Fig. 32 we may get a general idea of the appearance presented by
a male or female, lying back upwards in a small glass dish, ready for
examination with the pocket lens. The female may be distinguished at a
glance by her wingless condition--only rudiments of wing-cases being
present, and no wings--and her broader abdomen. In life she does not
stand so high upon her legs as does the male, and her abdomen trails
along the ground. The male does not acquire his wings till the last
moult.
[Illustration:
_Female._ _Male._
FIG. 32.--Cockroaches.]
As the Cockroach lies back uppermost in a glass dish, the head is
almost concealed. This is especially the case, unless the insect is
flattened out in some way, or pinned down to a piece of weighted cork.
There will thus be, apparently, two, instead of three main divisions.
This arises partly from the fact that the head is deflexed, or bent
down so that the mouth is turned towards the rear, and partly because
the first segment of the thorax bears a chitinous shield, roughly
semicircular, which covers so much of the head as would otherwise be
visible.
Public-domain text, read in full here on John Shaqi.
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