THE BED-BUG (_Cimex lectularius_)
In ‘x’ finita tria sunt animalia dira;
Sunt pulices fortes, cimices, culicumque cohortes;
Sed pulices saltu fugiunt, culicesque volatu,
Et cimices pravi nequeunt foetore necari.
(ANON.)
AMONG the numerous disagreeable features of the bed-bug is the fact
that it has at least two scientific names—_Cimex_ (under which name it
was known to the classical writers) and _Acanthia_. The latter name is
favoured by French and some German authorities, but _Cimex_ was the
name adopted by Linnaeus, and is mostly used by British writers, and
will be used throughout this article. One cannot do better than take
the advice of that wise old entomologist, Dr. David Sharp, and allow
the name ‘_Acanthia_ to fall into disuse.’
The species which is the best known in England is _C. lectularius_; but
there is a second species which is much commoner in warm climates, _C.
rotundatus_. As regards carrying disease, this latter species is even
more dangerous than its more temperate relative. Other species, which
rarely if ever attack man, are found in pigeon-houses and dove-cotes,
martins’ nests, poultry-houses, and the homes of bats.
[Illustration: FIG. 3.—_Cimex lectularius_, male. × 15. (From Brumpt.)]
The common bed-bug seems to have arrived in England about the same time
as the cockroach—that is, over four hundred years ago, early in King
Henry VIII’s reign. Apparently, it came from the East, and was for many
years confined to seaports and harbours. It seems to have been first
mentioned by playwriters towards the beginning of the seventeenth
century. The sixteenth-century dramatists could never have resisted
mentioning the bug had it been in their time a common household pest.
It would have appealed to their sense of humour.
How the insect got the name of ‘bug’ is unknown. It has been suggested
that the Old English word ‘bug,’ meaning a ghost or phantom which
walked by night, has been transferred to _Cimex_. This may be so, but
the ‘Oxford English Dictionary’ tells us that proof is lacking.
The insect is some 5 mm. in length and about 3 mm. in breadth, and is
of a reddish- or brownish-rusty colour, fading into black. Its body is
extraordinarily flattened, so that it can readily pass into chinks or
between splits in furniture and boarding, and this it does whenever
daylight appears, for the bug loves darkness rather than light. The
head is large, and ends in a long, piercing, four-jointed proboscis,
which forms a tube with four piercing stylets in it. As a rule the
proboscis is folded back into a groove, which reaches to the first pair
of legs on the under surface of the thorax. This folding back of the
proboscis gives the insect a demure and even a devout expression: it
appears to be engaged in prayer, but a bug never prays. The head bears
two black eyes and two four-jointed antennae. Each of the six legs
is provided with two claws, and all the body is covered with fairly
numerous hairs. The abdomen shows seven visible segments and a terminal
piece.
The bug has no fixed period of the year for breeding; as long as
the temperature is favourable and the food abundant, generation
will succeed generation without pause. Should, however, the weather
turn cold the insects become numbed and their vitality and power of
reproduction are interrupted until a sufficient degree of warmth
returns.
Like the cockroach, the bed-bug is a frequenter of human habitations,
but only of such as have reached a certain stage of comfort. It is said
to be comparatively rare in the homes of savages, but it is only too
common in the poorer quarters of our great cities. Its presence does
not necessarily indicate neglect or want of cleanliness. It is apt to
get into trunks and luggage, and in this way may be conveyed even into
the best-kept homes. It is also very migratory and will pass readily
from one house to another, and when an infested dwelling is vacated
these insects usually leave it for better company and better quarters.
Their food-supply being withdrawn, they make their way along gutters,
water-pipes, &c., into adjoining and inhabited houses. _Cimex_ is
particularly common in ships—especially emigrant ships—and, although
unknown to the aboriginal Indians of North America, it probably entered
that continent with the ‘best families’ in the _Mayflower_.
Perhaps the most disagreeable feature of the bed-bug is that it
produces an oily fluid which has a quite intolerable odour; the
glands secreting this fluid are situated in various parts of the
body. The presence of such glands in free-living Hemipterous insects
is undoubtedly a protection—birds will not touch them. One, however,
fails to see the use of this property in the bed-bug. At any rate, it
does not deter cockroaches and ants, as well as other insects, from
devouring the _Cimex_. There is a small black ant in Portugal which
is said to clear a house of these pests in a few days, but one cannot
always command the services of this small black ant.
Another remarkable feature is that the insect has no wings, although in
all probability its ancestors possessed these useful appendages. As the
American poet says:—
The Lightning-bug has wings of gold,
The June-bug wings of flame,
The Bed-bug has no wings at all,
But it _gets_ there all the same!
The power of ‘getting there’ is truly remarkable. Man, their chief
victim, has always warred against bugs, yet, like the poor, bugs ‘are
always with us.’ I heard it stated, when I was living in southern
Italy, that if you submerged the legs of your bed in metal saucers full
of water and placed the bed in the centre of the room, the bugs will
crawl up the wall, walk along the ceiling and drop on to the bed and on
to you. Anyhow, whether this be so or not, there is no doubt that these
insects have a certain success in the struggle for life, and only the
most systematic and rigorous measures are capable of ridding a dwelling
of their presence.
[Illustration: FIG. 4.—Egg of _Cimex lectularius_. Enlarged. (After
Marlatt.)]
The eggs of the bed-bug are pearly white, oval objects, perhaps 1 mm.
in length. At one end there is a small cap surrounded by a projecting
rim, and it is by pushing off this cap, and through the orifice thus
opened, that the young bug makes its way into the outer world after an
incubation period of a week or ten days. There is no metamorphosis—no
caterpillar and no chrysalis stages. The young hatch out, in structure
miniatures of their parents, but in colour they are yellowish-white and
nearly transparent. The young feed readily, and feeding takes place
between each moult, and the moults are five in number, before the adult
imago emerges. This it does about the eleventh or twelfth week after
hatching. These time-limits depend, however, upon the temperature after
hatching, and the rate of growth depends not only upon the temperature
but also upon the amount of food.
When bred artificially and under good conditions, the rate of progress
can be ‘speeded up’ so that the eggs hatch out in eight days, and every
following moult takes place at intervals of eight days, so that the
period from egg to adult can be run through in as short a time as seven
weeks.
[Illustration: FIG. 5.—Newly hatched young of _Cimex lectularius_.
1, Ventral view; 2, dorsal view. Enlarged. (After Marlatt.)]
Unless fed after each moult, the following moult is indefinitely
postponed. Hence it follows that in the preliminary stages bugs must
bite their hosts five times before the adult form emerges, and the
adult must, further, have a meal before it lays its eggs. The eggs are
deposited in batches of from five to fifty in cracks and crevices, into
which the insects have retired for concealment.
Bugs can, however, live a very long time without a meal. Cases
are recorded in which they have been kept alive for more than a
year incarcerated in a pill-box. When the pill-box was ultimately
opened, the bugs appeared to be as thin as oiled paper and almost so
transparent that you could read _The Times_[3] through them; but even
under these conditions they had managed to produce offspring. De Geer
kept several alive in a sealed bottle for more than a year. This power
of existing without food may explain the fact that vacated houses
occasionally swarm with bugs even when there have been no human beings
in the neighbourhood for many months.
The effect of their bite varies in different people. As a rule, the
actual bite lasts for two or three minutes before the insect is gorged,
and at first it is painless. But very soon the bitten area begins to
swell and to become red, and at times a regular eruption ensues. The
irritation may be allayed by washing with menthol or ammonia. Some
people seem immune to the irritation; and I know friends who, in the
West Indian Islands, have slept through the attacks of thousands of
bugs, and only awoke to their presence when in the morning they found
their night-clothing and their sheets red with blood, expressed from
the bodies of their tormentors as the victims turned from side to side.
As a rule, the uncovered parts of the body—the face, the neck, and the
hands—are said to be more bitten than the parts which are covered by
the bedclothes. This is not, however, my experience.
The bug has been accused of conveying many diseases—typhus,
tuberculosis, plague, and a form of recurrent fever produced by a
spirochaete (_Spirochaeta obermeieri_); but a critical examination
throws some doubt upon the justice of the accusation, and Professor C.
J. Martin writes as follows:—
There is really no evidence to incriminate the bed-bug in the case of
either typhus or relapsing fever. It is possible to transmit plague
experimentally by means of bugs, but there is no epidemiological
reason for supposing this takes place to any extent in nature.
There are two differences in the habits of bugs and those of fleas
and lice which may possess epidemiological significance. The first
concerns the customary intervals between their meals. Bugs show no
disposition to feed for a day or two after a full meal, whereas fleas
and lice will suck blood several times during the twenty-four hours.
The second is in respect to the time the insects retain a meal and
the extent to which it is digested before being excreted. Fleas and
lice, if constantly fed, freely empty their alimentary canals, and
the nature of their faeces indicates that the blood has undergone but
little digestion.
Both these insects evacuate such undigested or half-digested blood
_per rectum_ during the act of feeding, and the remnants of the
previous meal are thus deposited in the immediate vicinity of a fresh
puncture. It is not unlikely that, should the alimentary canal of the
insect be infected with plague bacilli, spirochaete, or the organism
responsible for typhus fever, these may be inoculated by rubbing or
scratching. Bugs have not this habit; and in all the cases I have
examined their dejections were fully digested, almost free from
protein, and consisted mostly of alkaline haematin.
Whether bugs be guilty of these crimes or not, they are the cause of
an intense inconvenience and disgust, and should, if possible, be
dealt with drastically. At the present time[4] there are rumours that
some of our largest camps are infested with these insects, and there
seems no doubt that some of the prisoners and refugees to this country
have brought their fauna with them, and this fauna is very capable of
spreading in concentration camps. The erection of wooden huts—no doubt
a pressing necessity—will afford convenient quarters for these pests.
Among the measures which have been most successful in the past has been
fumigating houses with hydrocyanic-acid gas; but this is a process
involving considerable danger, and should only be carried out by
competent people under the most rigorous conditions. In all fumigating
experiments every crack and cranny of a house should be shut, windows
closed, keyholes blocked, and so on. A second method of fumigation
is that of burning sulphur. Four ounces of brimstone are set alight
in a saucer, this in its turn is placed in a larger vessel, which
protects the floor of the room from a possible overflow of the burning
material. After all apertures have been successfully plugged, four or
five hours of the sulphurous fumes are said to be sufficient to kill
the bugs, but to ensure complete success a longer time is needed. This
is not only a much less expensive but a much less dangerous operation
than using hydrocyanic-acid gas. Two pounds of sulphur will suffice
for each thousand cubic feet of space, but it is well to leave the
building closed for some twenty-four hours after the fumigation.
Another more localised method of destroying these pests is the liberal
application of benzine, kerosene, or any other petroleum oil. These
must be introduced into all crevices or cracks by small brushes or
feathers, or injected with syringes. In the same way oil of turpentine
or corrosive-sublimate has proved effective. Boiling water is also
very fatal when it can be used; and recently in the poorer quarters
of London the ‘flares’ which painters use in burning off paint have
proved of great use in ridding matchboarding, or wainscoting, from the
harbouring bugs. Passed quickly along, the flame of the ‘flare’ does
not burn the wood, but it produces a temperature which is fatal to the
bug and to its young and to its eggs. And thus:—
‘This painted child of dirt, that stinks and stings’[5] is destroyed.