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Transcriber Note

Text emphasis denoted as _Italics_ and =Bold=.


  +-------------------------------------------------------+
  |        UNITED STATES DEPARTMENT OF AGRICULTURE        |
  |                                                       |
  |[Illustration]        =FARMERS'        [Illustration]  |
  |                       BULLETIN=                       |
  |                                                       |
  +-------------------------------------------------------+
  Washington, D. C.          754           October 14, 1916
  ---------------------------------------------------------
         =Contribution from the Bureau of Entomology,
                    L. O. Howard, Chief.=




                       =THE BEDBUG.=[1]


                      By C. L. Marlatt,

          _Entomologist and Assistant Chief of Bureau_.

[1] _Cimex lectularius_ L.; order Hemiptera, suborder Heteroptera,
family Cimicidae.



=CONTENTS.=


                                        Page.

  Introduction                               1

  Origin; common names; distribution         2

  Varieties and related insects              3

  General characteristics                    3

  The "buggy" odor                           4

  Habits and life history                    4

  Food and longevity                         7

  Influence of temperature                   8

  The bite of the bedbug                     9

  The bedbug and human diseases              9

  Natural enemies of the bedbug             10

  Remedies                                  11




=INTRODUCTION.=


The presence of the bedbug (fig. 1) in a house is not necessarily an
indication of neglect or carelessness; for, little as the idea may be
relished, this insect may gain access in spite of the adoption of all
reasonable precautions. It is very apt to get into the trunks and satchels
of travelers, or into baskets of laundry, and may thus be introduced into
homes. Unfortunately, also, it is quite capable of migrating from one
house to another and will often continue to come from an adjoining house,
sometimes for a period of several months, gaining entrance daily. Such
migration is especially likely to take place if the human inhabitants of
an infested house leave it. With the failure of their usual source of
food, the migratory instinct of the bedbugs is developed, and, escaping
through windows, they pass along walls, water pipes, or gutters, and thus
gain entrance into adjoining houses. In these or other ways anyone's
premises may be temporarily invaded.




=ORIGIN; COMMON NAMES: DISTRIBUTION.=


As with nearly all the insects associated with man, the bedbug has had the
habits now characteristic of it as far back as the records run. It was
undoubtedly of common occurrence in the dwellings of the ancient peoples
of Asia. The Romans were well acquainted with it, giving it the name
Cimex. It was supposed by Pliny--and this was doubtless the common belief
among the Romans--to have medicinal properties, and it was recommended,
among other things, as a specific for the bites of serpents. It is said to
have been first introduced into England in 1503, but the references to it
are of such a nature as to make it very probable that it had been there
long before. Two hundred and fifty years later it was reported to be very
abundant in the seaport towns, but was scarcely known inland.

[Illustration: Fig. 1.--Bedbug (_Cimex lectularius_): _a_, Adult female,
engorged with blood; _b_, same from below; _c_, rudimentary wing pad; _d_,
mouth parts, _a, b_, much enlarged; _c, d_, highly magnified. (Author's
illustration.)]

One of the old English names was "wall-louse." It was afterward very
well known as the "chinch," which continued to be the common appellation
for it until within a century or two, and is still used in parts of this
country. The origin of the name "bedbug" is not known, but it is such a
descriptive one that it would seem to have been very naturally suggested.
Almost everywhere there are local names for these parasites, as, for
illustration, around Boston they are called "chintzes" and "chinches," and
from Baltimore comes the name "mahogany flat," while in New York they are
styled "red coats," and in the west "crimson ramblers."

The bedbug has accompanied man wherever he has gone. Ships are very
apt to be infested with it and have been the chief means of its wide
distribution. It probably came to this country with the earliest
colonists; at least Kalm, writing in 1748-49, stated that it was plentiful
in the English colonies and in Canada, though unknown among the Indians.




=VARIETIES AND RELATED INSECTS.=


What may eventually prove to be mere variations of the ordinary-type of
human bedbug have been described as distinct species in several instances.
For example, the common bedbug of southern Asia is supposed to present
some slight variations from the European type, chiefly in being somewhat
more elongate. These slightly diverging forms of the bedbug in different
parts of the world, which are not known to have any special bird or animal
host other than human beings, may prove to be merely local races or
varieties of the ordinary bedbug.

Birds, bats, and poultry are attacked in various parts of the world by
a considerable number of parasitic bugs, closely related to the bedbug,
which live on their hosts and in nests and about roosting places. One of
these species, occurring abundantly in southwestern United States and
Mexico,[2] probably originally a parasitic messmate on birds and bats, has
come to be an unmitigated poultry pest, and from the close association in
these regions between poultry and human beings, is often a serious house
pest--more so even than the true bedbug. Others of the species infesting
birds and bats may also on occasion become house pests. For example, the
nests of the common barn or eaves swallow of this country often swarm with
the barn-swallow bug,[3] and from such nests under the eaves of dwelling
houses these bugs sometimes gain entrance to houses and beds and are the
cause of much annoyance. Similarly a species,[4] normally a parasite of
birds and bats in the Old World, and also in Brazil and the West Indies,
not infrequently becomes a human parasite.

[2] (_Cimex_) _Haematosiphon inodora_ Dugès.

[3] (_Cimex_) _Oeciacus hirundinis_ Jenyns.

[4] _Cimex hemipterus_ Fab. (synonym, _rotundatus_ Sign.).




=GENERAL CHARACTERISTICS.=


The bedbug belongs to the order Hemiptera, which includes the true bugs or
piercing insects, characterized by possessing a piercing and sucking beak.
The bedbug is to man what the chinch bug is to grains or the squash bug
to cucurbs. Like nearly all the insects parasitic on animals, however, it
is degraded structurally, its parasitic nature and the slight necessity
for extensive locomotion having resulted, after many ages doubtless, in
the loss of wings and the assumption of a comparatively simple structure.
Before feeding, the adult (fig. 2) is much flattened, oval, and in
color is rust red, with the abdomen more or less tinged with black.
When engorged the body becomes much bloated and elongated and brightly
colored from the ingested blood. The wings are represented by the merest
rudiments, barely recognizable pads, and the simple eyes or ocelli of
most other true bugs are lacking. The absence of wings is a most fortunate
circumstance, since otherwise there would be no safety from it even for
the most careful of housekeepers. Some slight variation in length of wing
pads has been observed, but none with wings showing any considerable
development has ever been found.

[Illustration: Fig. 2.--Bedbug: Adult before engorgement. Much enlarged.
(Author's illustration.)]




=THE "BUGGY" ODOR.=


The most characteristic feature of the bedbug is the very distinct and
disagreeable odor which it exhales, an odor well known to all who have
been familiar with it as the "buggy" odor. This odor is by no means
limited to the bedbug, but is characteristic of most plant bugs also. The
common chinch bug affecting small grains and the squash bugs all possess
this odor, and it is quite as pungent with these plant-feeding forms as
with the human parasite. The possession of this odor, disagreeable as
it is, is very fortunate after all, as it is of considerable assistance
in detecting the presence of these vermin. The odor comes from glands,
situated in various parts of the body, which secrete a clear, oily,
volatile liquid. With the plant-feeding forms this odor is certainly a
means of protection against insectivorous birds, rendering these insects
obnoxious or distasteful to their feathered enemies. With the bedbug, on
the other hand, it is probably an illustration of a very common phenomenon
among animals, i. e., the persistence of a characteristic which is no
longer of any especial value to the possessor. The natural enemies of true
bugs, against which this odor senses as a moans of protection, in the
conditions under which the bedbug lives, are kept away from it; and the
roach, which sometimes feeds on bedbugs, is evidently not deterred by the
odor, while the common house ant and the house centipede, which may also
attack the bedbug, seem not to find this odor disagreeable.




=HABITS AND LIFE HISTORY.=


The bedbug is normally nocturnal in habits and displays a certain degree
of wariness, caution, and intelligence in its efforts at concealment
during the day. Under the stress of hunger, however, it will emerge
from its place of concealment in a well-lighted room at night, so that
under such circumstances keeping the gas or electric light burning is
not a complete protection. It has been known under similar conditions to
attack human beings voraciously in broad daylight. It usually leaves its
victim as soon as it has become engorged with blood and retires to its
normal place of concealment, either in cracks in the bedstead, especially
if the latter be one of the wooden variety, or behind wainscoting, or
under loose wall paper, and in these and similar places it manifests its
gregarious habit by collecting in masses. It thrives particularly in
filthy apartments and in old houses which are full of cracks and crevices,
in which it can conceal itself beyond easy reach. As just noted the
old-fashioned, heavy, wooden-slatted bedsteads afford especially favorable
situations for the concealment and multiplication of this insect, and the
general use in later years of iron and brass bedsteads has very greatly
facilitated its eradication. Such beds, however, do not insure safety, as
the insects are able to find places of concealment even about such beds,
or get to them readily from their other hiding places.

Extraordinary stories are current of the remarkable intelligence of this
insect in circumventing various efforts to prevent its gaining access
to beds. Most of these are undoubtedly exaggerations, but the inherited
experience of many centuries of companionship with man, during which
the bedbug has always found its host an active enemy, has resulted in a
knowledge of the habits of the human animal and a facility of concealment,
particularly as evidenced by its abandoning beds and often going to
distant quarters for protection and hiding during daylight, which indicate
considerable apparent intelligence.

Like its allies, the bedbug undergoes what is known as an incomplete
metamorphosis. In other words, the insect from its larval to its adult
stage is active and similar in form, structure, and habit, contrasting
with flies and moths in their very diverse life stages of larva,
chrysalis, or pupa, and winged adult.

The eggs (fig. 3, _d_) are white oval objects having a little projecting
rim around one edge and may be found in batches of from 6 to 50 in cracks
and crevices where the parent bugs go for concealment. In confinement eggs
may be deposited almost daily over a period of two months or more and
commonly at the rate of from one to live eggs per day, but sometimes much
larger batches are laid. As many as 190 eggs have been thus obtained from
a single captured female.[5]

[5] Girault, A. A. Preliminary studies on the biology of the bedbug,
_Cimex lectularius_, Linn. III. Facts obtained concerning the habits of
the adult. _In_ Jour. Econ. Biol., v. 9, no. 1, p. 25-45. 1914.

The eggs hatch in a week or 10 days in the hot weather of mid-summer, but
cold may lengthen or even double this egg period or check development
altogether. The young escape by pushing up the lid-like top with its
projecting rim. When first emerged (fig. 3, _a, b_) they are yellowish
white and nearly transparent, the brown color of the more mature insect
increasing with the later molts (fig. 4).

[Illustration: Fig. 3.--Bedbug: Egg and newly hatched larva: _a_, Larva
from below; _b_, larva from above; _c_, claw; _d_, egg; _c_, hair or spine
of larva. Greatly enlarged, natural size of larva and egg indicated by
hair lines. (Author's illustration.)]

[Illustration: Fig. 4.--Bedbug: _a_, Larval skin shed at first molt;
_b_, second larval stage immediately after emerging from _a_; _c_, same
after first meal, distended with blood. Greatly enlarged. (Author's
illustration.)]

During the course of its development the bedbug molts or sheds its
skin normally five times, and with the last molt the minute wing pads,
characteristic of the adult insect, make their appearance. A period of
about 11 weeks was formerly supposed to be necessary for the complete
maturity of the insect, but breeding experiments with this insect,
conducted in this department in 1896, indicated that the life cycle is
subject to great variation, being entirely dependent on warmth and food
supply. Under favorable conditions of temperature and food it was found
that there was an average period of about eight days between moltings
and between the laying of eggs and their hatching, giving about seven
weeks as the period under these conditions from egg to adult insect. The
molting periods are shorter in the earlier stages and lengthen in the
later stages. There are many exceptions, however, and some individuals
even under the same conditions remain two or three weeks without molting.
Under conditions of famine, or without food, as already shown, the bedbug
may remain unchanged in any of the immature stages for an indefinite
time, and the checking of development by such starvation may result in
additional molting periods.

The breeding records referred to, and numerous confirmatory experiments
subsequently made by other investigators, indicate that ordinarily but one
meal is taken between molts, so that each bedbug must puncture its host
five times before becoming mature, and at least once afterwards before
it can develop eggs. Additional meals between molts may be taken under
favoring circumstances, however, and particularly when the insect has been
disturbed and has not become fully engorged at its first meal after a
molting or other period. The bedbug takes from 5 to 10 minutes to become
bloated with blood, and then retires to its place of concealment for 6 to
10 days for the quiet digestion of its enormous meal, and for subsequent
molting, or reproduction if in the adult stage.

Such feeding and reproduction may, under favorable conditions of
temperature, continue throughout the year, and in one instance the
progeny of a captured female adult was carried through three continuous
generations.[6]

[6] Girault, A. A. Preliminary studies on the biology of the bedbug,
_Cimex lectularius_, Linn. II. Facts obtained concerning the duration of
its different stages. _In_ Jour. Econ. Biol., v. 7, no. 4, p. 163-188.
1912.

Unfavorable conditions of temperature and food will necessarily result in
great variation in the number of generations annually and in the rate of
multiplication, but allowing for reasonable checks on development, there
may be at least four successive broods in a year in houses kept well
heated in winter.




=FOOD AND LONGEVITY.=


Under normal conditions the food of the common bedbug is obtained from
human beings only, and no other unforced feeding habit has been reported.
It is easily possible, however, to force the bedbug to feed on mice, rats,
birds, etc., and probably it may do so occasionally in nature in the
absence of its normal host. The abundance of this insect in houses which
have long been untenanted may occasionally be accounted for by such other
sources of food, but probably normally such infestation can be explained
by the natural longevity of the insect and its ability to survive for
practically a year, and perhaps more, without food.

There are many records indicating the ability of the bedbug to survive
for long periods without food, and specimens have been kept for a year
in a sealed vial with absolutely no means of sustenance whatever. In the
course of the department's study of this insect in 1896, young bedbugs,
obtained from eggs, were kept in small sealed vials for several months,
remaining active in spite of the fact that they had never taken any
nourishment whatever. A considerable series of experiments was later
conducted by Girault[7] bearing on the longevity of the insect under
different conditions. A large number of adults of both sexes were kept
in confinement, but with normal feeding and mating, and these survived
for periods ranging from 54 to 316 days. Similarly, the life of 71 newly
hatched larvæ, without food, ranged from 17 to 42 days, averaging about 28
days. Partly grown captured insects lived without further feeding from 17
to 60 days. Longevity is naturally affected more or less by temperatures.
In other words, temperatures sufficient to check the activity of the
insect and produce hibernation or semihibernation are apt to increase
longevity.

[7] Loc. cit.

The fact that the bedbug is able to survive for such long periods without
human blood has led to the theory that it could subsist in some fashion
on the moisture from wood or from accumulations of dust in crevices in
flooring, etc. There seems to be no basis of observed fact for this idea.

Another very prevalent belief among the old settlers in the West, that
this insect normally lives on dead or diseased cottonwood logs, and is
almost certain to abound in log houses of this wood, seems to be equally
devoid of basis. As illustrating this belief, the department has on
file a very definite report from an Army officer that the bedbug often
occurs in numbers under the bark of dead cottonwood trees,[8] especially
along the Big Horn and Little Horn Rivers in Montana. The basis of this
report and the origin of this very general misconception is probably, as
pointed out by the late Prof. Riley, due to a confusion of the bedbug with
the immature stages of an entirely distinct insect,[9] which somewhat
resembles the bedbug and often occurs under cottonwood bark.

[8] _Populus monilifera._

[9] _Aradus_ sp.




=INFLUENCE OF TEMPERATURE.=


As a messmate of human beings in dwelling houses, the bedbug is normally
protected from extreme cold, and is known to be an abundant and serious
pest far north. In fact, it is often more troublesome in north temperate
latitudes than farther south. This may be accounted for partly by the fact
that the bedbug is very sensitive to high temperatures, and a temperature
of 96° to 100° F. or more, accompanied with a fairly high degree of
humidity, results in the death of large numbers of the bugs. The mature
or partly mature bedbugs can stand comparatively low temperatures, even
below freezing, for a considerable period. The eggs and newly hatched
larvæ, however, succumb to a temperature below freezing, if this condition
is prolonged for from 15 days to a month. The feeding and developing
activity of the insect practically ceases at 60° F., the insect remaining
quiescent and in semihibernation at temperatures below this point. The
most favorable temperatures for activity are between 60° and 98° F.[10]
The activity of the insect is controlled entirely by temperature and food
supply, and, therefore, in heated houses the insect may remain active
throughout the winter. There is some protection in winter, therefore, in
sleeping in cold bedrooms.

[10] Bacot, A. W. The influence of temperature, submersion, and burial
on the survival of eggs and larvæ of _Cimex lectularius_. _In_ Bul. Ent.
Res., v. 5, pt. 2, p. 111-117. 1914.




=THE BITE OF THE BEDBUG.=


The bite of the bedbug is decidedly poisonous to some individuals,
resulting in a slight swelling and disagreeable inflammation. To such
persons the presence of bedbugs is sufficient to cause the greatest
uneasiness, if not to put sleep and rest entirely out of the question.
With others, however, who are less sensitive, the presence of the bugs
may not be recognized at all, and, except for the occasional staining
of the linen by a crushed individual, their presence might be entirely
overlooked. The inflammation experienced by sensitive persons seems to
result chiefly from the puncture of the skin by the sharp piercing setæ
which constitute the puncturing element of the mouth parts, as there seems
to be no secretion of poison other than the natural fluids of the mouth.

The biting organ of the bedbug is similar to that of other insects of its
order. It consists of a rather heavy, fleshy under lip (the only part
ordinarily seen in examining the insect), within which lie four threadlike
hard filaments or setæ which glide over one another with an alternating
motion and pierce the flesh. The blood is drawn up through the beak, which
is closely applied to the point of puncture, and the alternating motion of
the setæ in the flesh causes the blood to flow more freely. The details of
the structure of the beak are shown in figure 1 at _d_.

To allay the irritation set up by the bite of the bedbug, peroxide of
hydrogen, or dioxygen, may be used with good results.

Tincture of iodine either at ordinary or double strength is also a good
counter-irritant for use in cases of flea, mosquito, bedbug, and other
insect bites, but should be used with caution on the tender skin of
small children and on those who are affected with or disposed to eczemic
disorders.




=THE BEDBUG AND HUMAN DISEASES.=


In common with other insects which attack man and warm-blooded animals,
it is entirely possible for the bedbug and its close allies to be
transmitters of contagious human diseases, and already these insects have
been shown to be possible carriers or transmitters of a considerable
series of diseases, including infantile Kala-azar of northern Africa and
southern Europe, relapsing fever of Africa and Europe, the Chagas fever
of Brazil, tropical sore, plague, and possibly leprosy. In the case of
these, and perhaps other diseases, the bedbug shares the responsibility of
transmitter with other biting insects, such as body lice and fleas.

The particular role of the bedbug as a carrier of disease has not been
satisfactorily determined, nor has it been shown that the bedbug is a
necessary alternate host in any instance. In general, the transmission
of disease by this insect has apparently resulted from the accidental
carriage of the disease elements on the mouth parts, as pointed out by
André,[11] after a careful study of the subject. As a parasite of human
beings in private dwelling houses, where it may seldom change its host,
the opportunity for the bedbug itself to become infected with human
diseases and again to transmit them to the human subject is very remote.
This condition, however, does not apply to hotels or to passenger boats,
where the human occupants are constantly changing. Furthermore, the fact
that the bedbug attacks its host at comparatively long intervals of from
a week to several weeks or months acts as a bar to its transmission of
certain insect-borne diseases, the biology of which requires a definite
and comparatively short period of development in the alternate insect host.

[11] André, Ch. Recherches anatomiques et expérimentales sur la punaise
des lits. _In_ Jour. Physiol. et Path. Gén., v. 14, p. 600-615. 1912.




=NATURAL ENEMIES OF THE BEDBUG.=


Living always in houses as it does and being well concealed, the bedbug
is not normally subject to much if any control by natural enemies.
Certain other household insects, however, do occasionally prey upon the
bedbug, as, for example, the house centipede[12] and the common little
red house ant.[13] Such enemies, however, are of very small importance
and yield little, if any, effective control except under very exceptional
circumstances. One such instance is reported by the late Mr. Theodore
Pergande, of this department, who states that as a soldier in the Civil
War he occupied at one time a barracks at Meridian, Miss., which had
been abandoned some time before. The premises proved to be swarming with
bedbugs; but very shortly afterwards the little red house ant discovered
the presence of the bedbugs and came in enormous numbers, and Mr. Pergande
witnessed the very interesting and pleasing sight of the bedbugs being
dismembered and carried away bodily by these very minute ants, many times
smaller than the bugs which they were handling so successfully. The result
was that in a single day the bedbug nuisance was completely abated. The
liking of red ants for bedbugs is confirmed also by a correspondent
writing from Florida (F. C. M. Boggess), who goes so far as heartily to
recommend the artificial introduction of the ants to abate this bug
nuisance.[14] Bedbugs and other household insects, however, are not of the
sort which it is convenient or profitable to turn over to their natural
enemies in the hope that eradication by this means will follow, and the
fact that they are preyed upon by other insects furnishes no excuse to the
housekeeper for not instituting prompt remedial measures.

[12] _Scutigera forceps_ Raf.

[13] _Monomorium pharaonis_ L.

[14] Bedbugs and red ants, _In_ Insect Life, v. 6, no. 4, p. 340. 1894.




=REMEDIES.=


Undoubtedly the most efficient remedy for the bedbug is to fumigate the
infested house or rooms with hydrocyanic-acid gas. This gas will penetrate
into every crevice in the house or room where the bedbugs conceal
themselves and has an immediate effectiveness which gives it an important
recommendation, especially when the infestation is considerable or of long
standing. This method of fumigation should be intelligently employed,
as the gas is deadly poisonous. A bulletin giving directions for such
fumigation has been issued by the Department of Agriculture.[15]

[15] Howard, L. O., and Popenoe, C. H. Hydrocyanic-acid gas against
household insects. U. S. Dept. Agr. Farmers' Bul. 699. 8 p. 1916.

The fumes of burning sulphur are also a very efficient means of control
where the conditions are such that this method can be used, readily
destroying the insect in all stages, including the egg. The treatment is
inexpensive compared with the use of hydrocyanic-acid gas and offers much
less risk of danger to human beings. There is, however, a considerable
risk of injury to household fabrics, furnishings, and wall papers from the
strong bleaching quality of sulphur fumes. This danger will be somewhat
diminished if the fumigation can be done at a time when the room or house
is thoroughly dried out, as in winter by a furnace or other heating
system. Further precautions should be taken by removing all metallic
surfaces from the room or building, or by protecting them with a coating
of vaseline. Two pounds of sulphur are recommended for each 2,000 cubic
feet of space, and the building should be closed for the treatment for at
least 5 or 6 hours, or preferably for 24 hours. Sulphur candles may be
used where available, or the sulphurous gas or fumes can be generated by
burning the sulphur in a dish placed in the center of the room, and for
protection set within a larger vessel. Thorough-going precautions must be
taken to prevent accidental overflowing or the starting of a fire, and
after the fumigation the house should be given a thorough airing.

Other gases have been experimented with, such as formalin and the vapors
of benzine, naphthaline, and camphor, but these gases are of little value.
Similarly, insect powders are of little value, largely from the difficulty
of getting them into the crevices and other places of concealment of the
insects.

The old-fashioned household remedies referred to below are effective
enough, though at a greater cost of time and personal effort. They
will, however, be often of much service in the case of slight or recent
infestations, or where the employment of more poisonous and troublesome
gases is objected to or is impracticable. Of these simple methods of
control perhaps the most efficient is in very liberal applications
of benzine or kerosene, or any other of the lighter petroleum oils,
introduced with small brushes or feathers, or by injecting with syringes
into all crevices of beds, furniture, or walls where the insects may have
concealed themselves. Corrosive sublimate is also of value, and oil of
turpentine may be used in the same way. The liberal use of hot water,
wherever it may be employed without danger to furniture, etc., is also an
effectual method of destroying both eggs and active bugs.[16]

[16] A remedy for the bedbug has been devised by Mr. R. H. Pettit
("Notes on two insecticidal agents," in 10th Rpt. Mich. Acad. Sci., p.
159-160, 1908) as a substitute for hydrocyanic-acid gas and sulphur,
and is reported to have proved very successful. The preparation of this
insecticide and its application is described as follows:

  Alcohol is drawn through pyrethrum in a funnel until the powder is
  well washed and a large part of the resinous principle extracted. To
  do this, the powder is placed in a large funnel with filter-plate and
  a layer of cotton wool at the bottom. An aspirator is attached and
  the alcohol is at first slowly and later rapidly sucked through six
  or eight times, during which operation it becomes highly colored. To
  this liquid as a basis, are added several oils to give permanence
  to the application. Both alcohol and pyrethrum evaporate so quickly
  that it was thought best to carry in some heavier volatile oils whose
  effects would last several days or even weeks. The formula when
  completed stands as follows:

  To the extract made by washing 400 grams of pyrethrum with 2,000 c.
  c. of strong alcohol, are added--

      50 grams gum camphor.
      150 c. c. cedar wood oil.
      25 grams oil citronella.
      25 grams oil lavender.

  The application is best made with a large sized atomizer, one holding
  a pint or more and working with a piston instead of a rubber bulb.
  * * * To obtain the best results, repeat the treatment after about
  two weeks. We have tried this mixture repeatedly, and with uniformly
  gratifying results. Usually one application, if thoroughly made, put
  a period to the complaints, about eight or ten ounces being required
  in an average sleeping-room. The odor remains some little time in a
  room, but is not disagreeable to the average person.

  This remedy can be readily prepared by a pharmacist in any drug store.

Various bedbug remedies and mixtures are for sale, most of them containing
one or another of the ingredients mentioned, and these are frequently of
value. The great desideratum, however, in a case of this kind, is a daily
inspection of beds and bedding, particularly the seams and tufting of
mattresses, and of all crevices and locations about the premises where
these vermin may have gone for concealment. A vigorous campaign should, in
the course of a week or so at the outside, result in the extermination of
this very obnoxious and embarrassing pest.

The possibility of temperature control is indicated in the discussion
elsewhere of the effect of temperature on this insect, and it may be that
if infested houses in cold climates could be opened up and allowed to
remain at a temperature well below freezing for a week or more, the bedbug
would be thoroughly exterminated. This method of control would be rarely
practicable except perhaps in the case of summer houses which are left
untenanted in winter.


       *       *       *       *       *


=Transcriber Note=

Illustrations move to prevent splitting paragraphs. Minor typos may have
been corrected. Produced from files generously made available by USDA
through The Internet Archive. All resultant materials are placed in the
Public Domain.