Article beginning on page 117.
Psyche 12:117-123, 1905.

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19051 GIRAUZ1 AND STRAUSS-THB BEDBUG
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THE FOWL BUG, CLINOCORIS COLU'tfBAA'IUS (JENYNS) : HOST RELATIONS.
Adults and larvae attack dead and living mice (Mm) ; calumbariits feeds on human blood. I. Clinocoris lecttilizritts (Linnaeus). In experimental medicine, the host relations of our common bedbug are of importance from the fact that if they attack animals other than man, their scope in the potential transmission of diseases becomes greatly enlarged. In review- ing the entire enton~ological and medical literature, as far as it concerns the .
bedbug, the writers have been unable to come to any definite conclusion concern- ing these host relations. As far as the entomological literature is concerned, no conclusions at all are possible, for the simple reason that authorities differ, and that no definite experiments have been cited to show that the host of the bedbug is other than man himself. In fact, most of the statements to the contrary are purely conjectural or theoretical.
In the literature of experimental medicine, however, it has been quite fre- quently stated that bedbugs attack mice, living and dead, and these mice were so used in the experiments performed.
But the statements of these facts have
been so general, and in a way, so unscientific, that the writers could not, in strict justice, come to any other conclusion than that it was very probable that Z~cfuZa~iz~s attacked animals other than man. Nuttall (1897, IS@), in his most important experiments on the transmission of diseases by the bedbug, however, nearly convinces us that both living and dead mice are readily attacked by Jecfu- larius, but doubt could not be eliminated, because of the use of the general term wansen instead of a specific name, and on account of the presence of a
single ambiguous sentence (Nuttall. IS$$ p. 626, footnote). Correspondence with some of the leading hemipterists and personal com- munications from economic entomologists, all tend to throw doubt on the state- ments thus made in the medic-il literature. Scepticism coming from such sources cannot be better evidence, and practically shows that the question remains as yet unsettled.
'Clinocotfs is masculine, not feminine, as would be inferred from its ending. (Kirkaldy.)




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In view of the foregoing facts, and because of the importance of the ques- tion, the following preliminary and rather crude experiments have been per- formed, showing that ftnddarius will readily attack both living and dead mice. The experiments also explain to a certain extent, the supposed occurrence of the bedbug in long unoccupied houses, from the fact that writers, now, will not have to theorize in regard to moisture, and so forth as a food, in order to support their statements.
The specimens used in these experiments were all obtained by jarring beds in one of the large mission houses in the city of Washington, about 7 P. M., September the eleventh, 1905. They were then full-fed, and the majority of them in the last larval instar (instar V). They soon molted, and then, were specific- ally determined by comparison with specimens in the collection of the United States National Museum.
A.
Experiment wf/i a recently &ad mouse.
A single mouse killed in the insectary of the Department of Agriculture at 8.40 A. M., September aoth, was immediately placed under a large bell-jar, on a clean sheet of white paper.
I.
Nymph.
Six minutes afterwards, 8.46 A. M., a nymph in instar 111, which was starved when captured on September I ith, was placed under the bell- jar.
It was nearly transparent. The larva paused a few seconds, and then went to the carcass ; at 8 :46:3 j A. M., it was feeding from the toes of the left hind leg, from which it was apparently unable to extract much blood. At 8.5 I a. m,, it left the toes and crawied completely around the head end of the body to the right hind leg, and there again attempted to feed from the toes of that leg, but with little or no success.
At 8:53:30 A. M., it left its last position, crawled around the head end of the body, and attached itself to the abdomen. Up to this moment, the larva was but slightly tinged with blood. Attached to aLido- men at 8:54 A. M.; larva's abdomen red from blood at 8: 34;30 A. M.; larva halt full of blood at 8:57 A. M. The larva appeared to be weak, and was having much trouble to obtain blood. After 9 A. M., the larva remained the same, as far as the amount of food obtained is concerned, but frequently changed its position on the carcass. It was removed from the carcass at 10:30 A. XL, having voluntarily left it at 10:20.
The body of the mouse was getting cold at 9:08 A. M". The larva was not fully gorged with blood, but it is evident that this was due to its weakness, a condition apparently due to its age, combined with its previously starved condition. Cases of this kind are often met with in this species. It molted on September aSth, without having been f



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2. Adult.
An adult, not recently fed when captured on September nth, was placed under the bell-jar at 936 A. M. The body of the mouse was then cold, and a little stiff.
The adult wandered about, and then at 9:27:30, crawled under the carcass ; body then flat and fully colored. Hiding from light. In a few minutes, crawls
,
from beneath the carcass to the side of the bell-jar, not having fed. Jar covered
with a black cloth
At 9:44 A. M., jar uncovered and the adult found fully gorged with the .
blood from the carcass. It was found at rest on the back of the mouse, but began to wander on exposure to the light. Body of mouse now stiff and cold. Adult removed.
Another hungry adult placed under the bell-jar at I I A. M., the mouse then being dead 2 hours and 20 minute% It was pale, having just recently passed the fifth ecdysis.
At once hid under the carcass.
It did not feed up to 3 P. M., and was then removed. The blood in the car-
cass had by that time coagulated. Experiments discontinued on account of the lack of material.
B. Experiment with a living mouse.
A mouse trapped in the insectary of the Department of Agiculture during the night of September 2 1-2 2, 1305, was confined under a bell-jar as in the first experiment at g A. M., September ~2nd.
At 9:40 A, M., three adults, captured when full-fed in instar V, on September nth, and since molting on September the 18th~ and a single larva ininstar IV, hungry when capture'!, were placed under the jar and the latter covered with a black cloth to exclud 5 the light.
None of the insects had fed up to 6 I?. M. At 7 A. M,, SeiLember the ssrd, the day following, the cloth was removed from the jar, and ali 3f the insects found fully gorged with blood, the abdomens of the adults imm b.isety swollen.
Upon exposure to the
wandered quickly a )out. The experiment was not repeated +
of enough suitable 'nateria1,-hungry bedbugs. C-
Experhen/ 'i'iffi remt t/r born mice.
At 6-30 P. M., September 2Sth, three recently born mic group on a clean sheet of
white paper and covered with a small bell-jar. Although much alive, their bodies were cold. Immediately afterwards, three adults of leciularius, full-fed nymphs in instar V when obtained on September I ith, molting on September igth, and now, therefore, hungry adults, were introduced. Left over night in a dark room.




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At 7 A. M., September agth, adults found greatly swollen with blood from the mice. The latter still alive. tf
These experiments show clearly enough that Zcctitlarius will readily feed on mice, at least under the conditions in foregoing. It has nnw to be proven
whether or not they can breed under such conditions. There appears to be no
reason why they cannot, yet experiments are necessary to prove that they can. The writers have been unable to experiment in this direction because of the diffi- culty experienced in obtaining either eggs from confined adults, or very young nymphs from other sources.
It is hardly necessary to say that more experiments are needed on all points --
in the question involved. '
IL
CUaocori~ cohtmbarius (Jeny ns ) .
As with lecfdariml so with this species. The host relations are entirely
unknown.
That is, the statements concerning these relations are so confusing, that no positive conclusions are possible. The following preliminary experi-
ments may help to a better understanding of them. Thirty-two specimens, in all stages, were obtained on September 2+th, 1905, from a chicken house, in a large fowl yard at Anacostia, D. C. The house in
which they were found was a barn-like structure, consisting of an elevated first floor and a loft above. On the former, which consisted of a main hallway run- ning the entire length of the building, and of pen-like rooms of rather large dimensions, un each side, made of closely fitting laths coated with whitewash, was occupied entirely by chickens.
Each room contained about three nests,
made of boxes filled with straw.
The loft above was occupied by pigeons.
, The first floor of the structure was reached from the ground by means of a stairway.
The building itself was surrounded by quite extensive yards, all alive with different kinds of poultry and pigeons, and was not very distant from the dwelling of the superintendent.
The bugs were not easily found at first. In fact, none were found in the
nests.
The first sign of their presence was found in the spider nests along the .
walls, which sometimes held large masses of dead bugs and exuviae ; generally, however, but one or two. Finally, the insects were found hiding in cracks between the laths, or in dark corners of the room ; in such places, eggs were quite frequently found. Nearly all of them were full-fed, showing a constant supply of food at hand. They were in all stages, and it was quite difficult to dis- lodge them. The attendant, who was following, said that no bugs were present. But a casual observer would hardly have noticed their presence.



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190~1 GIRAULT AND STRAUSS-THE BEDBUG 13 I It struck the writers at once, that an excellent opportunity here offered to prove whether or not this species would naturally leave their preferred hosts chick&, and go to the dwe11ings of mw, or whether they wo111d crawl onto man, thus be transferred to his dwellings, and breed there. But this could not be , determined because of the absence of the superintet~dent, and nothing could be .obtained from the attendant, who denied all knowledge of bugs, especially those found in beds.
This species found associated with chickens agrees 41 with the description of colitwban/u given by Osborn ( q), and they agree with supposed specimens of that species now in the collection of the United States Xational Museum. On , ,
comparison with other species in the National Museum collection, they are at e
once easily separated from the species associated with the bat (pipi.rtrelH Jenyns), and with the swallow (hir/wilhis Jenyns). They are closer to /ec/dizH~~.c, but differ in the shape of the body, which has the greatest width of the abdomen at the middle, and which, in general, is smaller, and in the relative lengths of joints 3 and 4 of the antennae, which are subequai in cohtmbarius, but joint 3 much longer than 4 in I^cfularius. They cannot possibly be hthitt iuo~-durit Dugk The specimens in the National Museum are from the United States. A. Experiment wii!t human blood.
At 6.45 b. M., September zSth, an adult of this species, full-fed when cap- tured, was placed into a small glass via1 and the latter then inverted over a por- tion of the fore arm, just above the wrist In this way, the insect was forced to rest on a portion of the skin.
Upon regaining its position, after the fall down the sides of the vial, it remained perfectly motionless for nearly a minute. Then, very quietly, it inserted the beak and began to feed. In ten minutes, it was gorged with blood, and the body was therefore much elongated. About eleven minutes after begin- ning to feed, the bug witl~drew its beak, its body greatly distended with blood. &other recently fed adult captured on September sith, showed willingness to feed from the fingers of the hand on the afternoon of September zqth, when they were placed near it.
Accordingly, it was transferred to a vial, and the latter inverted over a por- tion of the under surface of the fore arm, at 6:08 P. M., in the presence of a bright light.
It tried to escape at first, but at 6:oq P. M., it inserted the beak and began to feed.
The vial was then removed, leaving the insect attached to the arm. It was wholly unmindful of the light. The abdomen gradually commenced EO



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merit.
3. Experiments with lii'iq mice.
At 8 P. M., September Sth, three recently born mice were placed under a bell-jar, and three adults and two Iarvse: of columbarius added. They were left
over night in a darkroom, and were found gorged with blood on the morning of, September the agth.
-- . .
While placing them under the bell-jar the evening before, one of the adults 4
I ,
accidently fell on the body of one of the young mice, which it i~nmecliatciy attacked. When its beak was inserted, the mouse jumped from the pain, and a + .
straggle then ensued, the almost helpless little animal trying desperatively to dis- lodge the sucking insect by rolling and kicking. Several times, the bug lost its hold. but turned at once and renewed the attack, until at last, it obtained a position on the breast of the mouse, between the fore legs, where it was simply impossible for it to be reached.
Here it fed until satisfied.
The insects showed no hesitancy in attacking these mice, after gaining access to them; but on account of the presence of light being necessary in order to watch them, they would not as a general rule, go at once to feed. Some do not seem to mind the light at all, however. This is seemingly dependent on the state of their appetite,
At 7.30 P. M., September the qth, the experiment was repeated, using the same mice, now nearly exhausted from lack of nourishment. Two adults and one larva were left over night with the three mice. The following morning they were gorged with blood. The mice were dead. Young mice
are very sensitive to the attacks of these insects:. They start with pain when bitten, and in their helpless way, struggle frantically to keep the + insects away, or to dislodge them. But the activity and persistency of the "bed- bugs make their struggles useless,"
The writers could not find any marked differences between 2ect;darius and '




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pp. 12, 157-160, 162, I%, figs. 88-89, 92 b. Et cf. pp. 286-287.
18g7._Nuttall,-George~H.-F~- Zur-Aufklarung -del~RoHe, welche -diepÌÔ Insecten bei der Verbreitung der Pest spielen.-Ueber die Empfindlichkeit vers- chiedener Tiere fiir dieselbe. Eine experimentelle Studie. Centra1blat.t f. Bakteriologie, Parasitenkunde, u. Infectionskrankheiten, Jena, Bd. XXII, erste abteilung, pp. 91-93.
(Versuche mit Wanzen.)
~898.
Nuttall, George H. F.
Zur Aufklaruag der Rolle, welche stech-
ende Insekten bei der Verbreitung von Infektionskrankheiten spielen. Infek-
tionsversuche an Mausen mittels mit Milzbrand, Huhnercholera und Mausesep- *
tikamie infiezierter Wanzen und Fltjhe.
Centralblatt f. Bakteriologie, Parasitenkunde? u. Infektionskrankheiten. Jena, Band XXIII, erste abteilung, pp. 625-635. Reviewed by Kubler, ib., 1899.
The writers are indebted to Dr. L. 0. Howard, Chief of the Bureau of En- tomology, U. S. Department of Agriculture, for his kindness in permitting the publication of this paper.




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