IOSQrITO CON "I "IONS
UTI1' 7" FITY P ?.'RIDA
WVith an account of exneriTments conducted with
tro s for adult mosquitoes
U. CAR. LOFTIV
?. S. '. C. A. & College
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A thesis submitted to the faculty of the university of Flbrida
for the degree of master of science
MAY 20, 1913
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Soecies found with descriptions and
Yosouitoes and Disease
Prev ntives and Remedies
Remedies against Larvae
"Low the work at the University can be done
Description of trap
Habits of Mosquitoes
Size and Shape of traps
Position of Traps
Effect of color and cloth lining in the boxes
Effect of wind on Yumber cauo'ht
Effect of temperature on number caught
Attraction-s used in r-aps
Dopellants us,. in trap
Relative abundance duarinj t:' year
Practical use of traps
MOSQUITO CONDITIONS OF THE UNIVERSITY OF FLORIDA
Mosquitoes have been known to man since time imme-
morial, but so far as we know, there has been only one man
who was thankful for their existence. In the Old Testament
we find that when iKing Saul was seeking David to slay him, he
was asleep in a cave one night when David entered and secOured
his spear and a bit of his robe. In the Talmud version of this
story, we are told that King Saul was guarded by Abner who had
stretched himself across the entrance of the cave so that David
had to crawl over him to enter. As David wa" leaving Abner
turned and threw his l13 over David's ankle. If Devid r.oved,
and death would follow. The Lord seeing -.avid's predicament,
sent a mosquito to bite Abner and cause 'im to move his foot,
thus fre in. David who went away thankful and _raisin.' God for
sending the mosquito. Since that time, man has considered
them a nuisance, lot only this, but the more recent discov-
veries have shown th:' to be transmitters of disease and one
of the greatest menaces to public health with which we have to
Mosquitoes are found everywhere, from the frozen
arctic regions to the depths of the tropical jungle. W en
Linnaeus, in 1758, published his catalogue of all the animals
then known to exist., he recorded only six species of mosquitoes.
Theobald, (1901) in his L"onoraph of t. e C licidae of t-3
World, listed about six hundred species, over sixty of which
are r corded front t>-t. United States.
Naturally the first question that arises is,
"Where do all these pests come from?" "Where do they
breed?" It is now known that with a few possible ex-
ceptions that do not occur here, that all mosquitoes are
aquatic in their younger stages. They live under the sur-
face of the water but are true air-breathers without gills
and must come to the surface for air. The air is taken in
through the trachael tubes which end in the prolongation
of the eighth abdominal segment, called the anal or re-
spiratory tube. This tube is pushed through the surface
film and a supply of air drawn in. Later, in the pupal
stage, they breathe through two trumpet like tubes arising
from the top of the thorax. The food of these larvae con-
sists of bacteria, slimes, and decaying animal and vegetable
matter, while a few are carnivorous. Different species
breed in different kinds of water. Some will breed only in
salt water, others in clean fresh water, while still others
prefer polluted sewerage. In studying the mosquito ques-
tion for extermination, it is important to know "'here and
what kind of breeding places we have to contend with.
The mosquito conditions here are very different
from many places in the United States. We are not surround-
ed by salt marshes with their hordes of pests, but during
the winter months when states farther north are enjoying
immunity, we. have them constantly buzzing around. The
Board of Control, realizing what a menace they were, appro-
priated nearly $1,000 in 1911 to screen the dormitories.
While this has been a great relief, they are still very
troublesome and the University Infirmary records show
that nearly one half of all the cases treated at the In-
firmary are. for malaria.
We are fortunate in having only fresh water
species that breed locally to contend with. On the north
and north-west of the University Campus, we have a slug-
gish branch of Hogtown Creek, which is little more than a
flat, boggy marsh. It begins at a point about north of
Science Hall and continues westward for nearly a mile be-
fore it joins a deeper, more rapidly moving stream. This
marsh is irregular in shape and size, depending upon the
season of the year. During dry weather, such as we hale
had in the winter and spring of this year, there is not
very much ground covered with water. During the rainy
season it is about fifty yards wide at the eastward end,
gradually widening until it reaches a point nearly back
of the Pepper house, covering four or five acres in this
area. From here it decreases in width, but later widens
again, spreading over considerable area.
'At first sight, this would seem to be an ideal
breeding place, but larvae-have never been found in large
numbers in this area. The water is stocked with aquatic
and semi-aquatic vegetation and always seems clean and
fresh, which does not make very attractive breeding ground
for Culex pipiens. There is also considerable aquatic life,-
minnows, dragon-flies, etc., in the deeper more permanent
portions which hold the larvae in check. I have never
taken larvae from the deeper portions, but both Culex and
Anopheles have been found along the edges and in holes
filled during the summer rains, though never very abundant.
From the past year's observations, this cannot be consider-
ed a very dangerous breeding ground.
There are several dwellings bordering this marshy
area on the south (near "College Inn") and some negro huts
on the north. There are the usual number of tubs, buckets,
and barrels generally found about the premises of second-
class suburban houses and although I have never found larvae
breeding on these premises, they have not been watched very
closely and probably breed some Culex and Stemomyia.
Continuing eastward along University Avenue, we
find several residences facing the street, and negro quart-
ers to the n-orth and north-east. At Robert Dixon's, a
negro living just behind Dr. Bernard's, and not three hund-
red feet from the street, I have never at any time during
the entire year failed to find large numbers of-Culex in
all st-ges -f development bre ding in his open well and
the buckets, barrels, etc., used for watering horses and
for washing. Stegomyia have also been found on these prem-
ises breeding in an old pot and a five-gallon tin can.
They have also been taken from old cans and crockery, on
a rubbish pile near >ere. These oremites ha e furnished
a goodly portion of the mosquitoes thet were so numerous
and annoying around the dwellin-s in this section durin-
the past year, and some have probably flown as far as the
University. A number of temporary pools formed by the rains
in this region we _e examined several times during September
and October, but no larvae were found.. Although no larvae
have been found at any of the other negro houses in this
section, there are some old cans, buckets, etc., around the
premises that are to be looked upon with suspicion.
The eastern portion of the campus, has furnished
unusually good breeding places during the year. During
the summer there was a lot of heavy hauling over the Campus,
in the vicinity of the new Language Hall. These ruts were
filled by the rains, and the water pumped from th- base-
ment of th- buildin-, and while their position was frequent-
ly changed, the old ruts furnished brc-'ding places for both
Cules and Anopheles. Larvae were found here from September
20th until YTovember 15th. As soon as the work was begun
in preparation for Language Hall, several trees were remov-
ed and large stump holes left. There were several of
these near the building that bred millions of Culex. Even
when the water smelled very strongly of turpentine and ap-
peared to be covered with a film of it, they were found.
Sometimes these holes would dry up to later be filled with
the rains, but larvae were found here at intervals until
the latter part of December, and once during February.
The excavations for Language Hall were begun during
the first part of August, and were almost immediately
filled with water, but the water was frequently disturbed
by the workmen in laying the foundations and the pumps
that were kept running most of the time. This disturbance
and frequent change probably kept the larvae out for it
was September 25th before any eggs were found. The larvae
found here were always sluggish and developed slowly, prob-
ably due to insufficient food, since the water contained
very little decaying material.. The surface of the water
was usually covered with a scum formed by the fine parti-
oles of brick, mortar, saw-dust, eto., that filtered down
from above. Larvae were found under this scum when it
seemed to be an eighth of an inch thick. Culex larvae
were found at intervals here until January 1st, and once
during February. The cement floor was finished in April,
thus keeping all the water out.
On the east of the campus, in "University Place"
there was another marshy area somewhat similar to the one
on the north. It extended diagonally across the field in
a south-eastern direction from the corner bounded by Uni-
versity Avenue and the Ocala Road, to a point nearly back
of Hon. Frank Clark's house. A ditch formed the central
channel, bounded on either side by a marshy area, varying
in width from about thirty yards at the end near the Uni-
versity, to zero at the other end. The whole place was
overgrown with weeds and briars during the summer an. sup-
ported considerable aquatic life. The water in the ditch
was usually moving and was free from larvae. Pools formed
in the marsh were sometimes found with both Culex and Anoph-
eles.. While the larvae never seemed very abundant here,
unless one considers the area covered, it was constant
source of supply. During the winter the whole place
has been drained and filled in so that this area is now
safe. Culex larvae have also been taken from Dr. Berger's
cess-pool and a tub in his back yard.
On the south there are very few breeding places.
We find several sink holes that are generally supposed to
be ideal breeding places. These are deep fresh-water holes,
usually with no inlet or outlet and full of various water
weeds, one sink being covered with duck-weed. These sinks
are all well stocked with fish ( :oggle eyes and minnows)
that keep the mosquitoes in check. I have examined these
sinks several times, but no larvae have been found.
Several times during the summer, water collected
in the basement of the Experiment Station b ilding and bred
both 2ulex and Anopheles. This seemed to be especially suit-
ed for Anopheles and they were frequently more nuiaerous
then the Culex. Two tubs filled with water, into which a
handful of bluestone was thrown, have been standing ere
all the year, but no larvae were found in them until this
spring, when they bred enough to be annoying at the Exper-
The campus is bounded on the west by another
marshy a-ea into w'ich the University :-ewerage empties. It
is a woods thickly covered with underbrush, with two main
strear-s and the boggy areas of the same general type of
those found on the north and o-.,st. The ground has more
fall, th. ditches have .good currents, and there are not so
many puddles as in the marshes on the north and east. How-
ever, the sewerage empties in here and for:'s some choice
places for Culex. Within fifty feet of the kitchen door,
where the ':itc'en sewerage is emptied, there are puddles
that have been teeming with Cul :x larvae all the winter.
No other larvae have been found here, but several Stegomyia
adults were taken from the woods in this vicinity and were
probably bre dingn nearby.
The excavations for the swimming pool which were
started during the summer, wer- filled by the rains and bred
millions of Culex and Anopheles. Large numbers of Anopheles
larvae were found at intervals until the pool was filled for
use in the middle of November. A few egg rafts have b en
found since then, but the water is emptied frequently enough
to be harmless.
The following species have been taken, but there
may be others that occur rarely:
Culex Quinquefasciatus Say
Anopheles crucians Wied.
Anopheles quadrimaculatus Say
Stegomyia calopus leig.
Psorophora ciliata Fab.
Psorophora floridense D & K
Following is a brief description of these speci-s.
Es.- This is the commonest species. The eggs are some-
what conical in shape and are laid on the surface of the
water with the large end down, They are placed side by side
and stuck together, forming a boat shaped raft (Fig. 1) of
six to thirteen rows with forty eggs in a row each raft con-
taining from one hundred to four hundred eggs, with an aver-
age of one hundred and seventy-eight and four tenths (Davis,
1906). They are white when freshly laid, but soon turn gray-
ish brown to black as seen from above, and silvery grayish
below, due to a film of air which protects the eggs from
the water. They usually hatch in from sixteen to twenty-
four hours but they have remained unhatched in the labora-
tory for ten to twelve days. A few hours dessication kills
them. (Mitchell 1907).
The eggs are usually laid at night or early
morning, but I have observed a female finishing a raft as
late as 9:30 A. M. on a bright day. Males and females
bred from larvae in the laboratory, have been confined in
a breeding cage for four weeks with a diet of fresh and
dried fruit, but never have any eggs been deposited unless
they -;ere fed a m al of blood. Smith (1908) states that
blood is the preferred food but is not a necessity and he
has had females ovipost on a diet of foul water.
Larvae.- The larvae issue from the under side of the eggs.
They hcve long anal tube and float below the surfact at
an oblique angle (Fig. 2). The anal tube is about five times
as lone as wide, tapering rapidly toward the last half and
bears four tufts (Fig. 3) -The antenal tufts are set in a
notch on the apical half, and are never over half the length
of the antenae. (Fig. 4)
The larvae, (Fig. 5) vary in color from light, al-
most colorless, to greenish, and nearly black, depending
upon the food. Larvae that have had scant food supply
developed slowly and seem to be lighter colored than those
that developed quickly. The larval stage lasts from seven
days (HovIard 1902) to several months. Smith (1908) has
found the time in New Jersey to vary from one to three weeks
depending upon the temperature and the food supply. The
time reuoireC here W :s about two weeks in September and
October, but was probable longer during the winter. In one
instance, in 'a:- they reuoired only seven days to pupate
while they have been kept in the laboratory from October
twenty-first to February third and then died before pupating.
The usual tive reuoired in the laboratory was four or five weeks.
The food consists of minute algae, bacteria, and
decaying vegetable material. They browse over the vegetable
material and eat the bacteria, slime, etc., that accumulates
there, as well as some cellular tissue, but no animal tissue
has been found in the stomachs examined (Johnson 1902).
They have frequently been observed nibbling over the bodies
of the larvae that had died, and in one instance the larvae
Cithoronia re-alis, but they may have been eating only the
Pupae.- The pupae are easily distinguished front the larvae
by their enlrged head and thorax. Tho trumpet like breath-
ing tub ,s which are over six tires as long as wide (Litch-
ell 1907), now arise from the dorsum of the thorax. The
pupal stag-e lasts from two to several days.
Adults.- The adults, (Fig. 6) are small to medium sized
individuals, usually: light bro-n color, though varying
from li-ht -reen to almost blach. The 'bdominal seT-ents
are banded b-sally with white, usually conspicuous, but
soneti-mes indistinct. They rest upon the -0all (Fi-. 2) in
a horizontal position, wit the hea' up-arJ, "id tfe body
held parallel to the wall.
The acutellum is three lobed with the posterior
end of the thorax bare. The palpi in the males are as long as
the proboscis, but in the female lass th'n one half as
long. The antennae of the males (Fig. 8) are thickly cov-.
ered with hairs, but in the females, spamesy covered (Fig. 9)
The front claws of the male are toothed, but single in the
female, with the tarsi uniformly blackish. The veins of
the wings (Fig. 10) are uniformly covered with narrow scales.
Tha petiols of the first submarginal cell is about one fourth
the length of the cell. They do not fly far, but several
hundred yards may be .covered when seeking for food or bread-
ing place (WSith 1903)
The length of life of the adult is ver- variable.
In the north the impregnated females hibernate over winter
and they may live several weeks and lay two or three times.
They have lived for five weeks in confinement in breeding
during April and May) an a ration of dried fruits.
Larvae have been ;aken in holss and yud les
around the edge of the marsh north of the campus; in
ells, bucket, andl arrel at Robert Dixon's; in stump holes
and wells around Language Hall; in basement of Language
Hall; in wagon ruts and several holes in this portion of
the campus; in barrels around Language Hall; in marsh and
ditch in University Place; cess-pool and tub at Dr. Berger's;
road ditch near Dr. Berger's; hole from cess-pool near
Science Hall; dish s in laboratory; basement of Experiment
Station Building-; tubs in basement of Experiment Station;
tubs at green house; marsh west of the University Commons;
swimming pool; cess-pool back of Thomas Hall; and several
other places too far away to affect the Unive sity.
Egs.- The eggs are boat shaped, one side being flatter
than the other, and are covered with a fine reticulated
membrane(Fig.11) They are not stuck together in rafts,
but float singly or in groups upon the surface of the water.
They usually hatch in thirty-six to forty-eight hours, but
they may remain viable for several months (Mitchell 1907)
They have remained unhatched for fifteen days in the lab-
Larvae.- The larvae are easily distinguished by their
resting position in the water (Fig. 12). They have 'a very
short anal tube and the body is always held parallel to
and touching th-b surface, and are supported ')y the anal
tube and the racemose hairs. (Fig. 13) along the sides of the
body indenting th; surface film. (Berkely 1902)
The color varies from very light green to dark
brown, almost black. There are often whitish markings on
the thorax .nd abdomen, but these are very variable and often
entirely lacking. The length of the larval stage under fav-
orable conditions,nmay be as short as six days (Howard 1902),
but is often much longer. Anopheles quadrimaculatus'has re-
mained in this stage for two months in the laboratory.
The larvae feed at the surfa e and will swallow
any minute floating particle.
Pupae.- The pupae resemble Culex very much, bu' they
have shorter and broader respiratory tubes which are placed
nearer the middle of the thorax. The length of the pupal
stage is longer than for Culex, varying from five to ten
days (Howard 1902).
The eggs, larvae, and pup:e of the tw;o species
we have are very much alike, and are not easily distinguish-
Adults.- The adults of this species are easily recognized
by the position in which the body is held when at rest,
(Fig. 14). It is held at an angle to the surface, which
gives then the appearance of standing on their heads.
The body o' A. crucians is usually held at an angle of
sixty to -eventy degrees, while A. quadrimaculatus usually
forms an angle of forty-five to fifty degrees. When there
is a breeze blowing, they have been observed clinging to
the screens at Shaw's in the position assumed by Culex, and
once or twice when the wind was blowing hard, the body was-
pressed against.the screen. 7vhen resting, the hind feet
usually point backward and are held a little below the level
of the body.
The scutellum is convex behind and the proboscis
is straight. The palpi are as long as the proboscis, (Figs.
16 & 17) and the claws simple in both sexes. The wings are
spotted with white and black scales, but the front margin is
wholly black scaled.
Anopheles crucians can be distinguished from
Anopheles quadrimaculatus by the spots on the wings. In
A. crucians, (F1g. 18) the la:t vein is white scaled
marked with three black spots; while in the A. quadrimaculatus
(Fig.19) the last vein is wholly black scaled.
The length of,life of the adult is variable. They
must live for at least a week after biting before they can
transmit malaria. In the north, they hibernate as adults in
cellars, barns, etc. (Howard 1911) They fly only short dis-
tances. In the work at Panama, three hundred yards from the
breeding points has proved to be safe.
Anopheles usually bite only at ni-'ht and this
point has been emphasized in protection from malaria, but
bo h A. crucians and A. quadrimaculatus have bitten in the
late morning in the Expermiment Station toilet.
Larvae have been taken in edges of the marshes
north of the campus and in University Place; in road ditches
nar east gate of campus; in basement of Experiment Station
building; -in pool south of Magnolia Park; in swimming pool;
and in several other places that were a mile or more from
the University.. They have been several times taken with
Eg.s.- The eggs are laid singly as .i7th Anopheles. They
are black in color, conically elongated, and are covered
with a reticulated membrane which collects air and gives
them buoyancy (3erkley 1902, Art. by Dr. Agromonte) They
usually hatch in from fifteen hours to three days, but will
stand dessication for a day or two and remain viable for at
least a nonth. (loc. cit)
Larvae.- The larvae closely resembel those of Culex, but
are larger, less active, and remain below the surface much
longer. The anal tube is somewhat shorter and thicker than
Culex, being about three times as long as wide, and tapers
regularly. The anal tube bears but one pair of tufts and
has the teeth of the pecten eve-ly spaced. The antennae
do not taper apically and the tuft is placed at or before
the middle. The length of the larval stage varies "rom
eight to twenty days.
Pupae.- The pupae (Fil. 20) resemble Culex, but are larg-
er They remain as pupac two or three days.
Adults.- The adults are easily recognized from the cut
(Fig. 21). They have the legs and abdomen conspicuously
banded with white and the dorsum of the thorax bears a lyre
shaped area of white, though this is sometimes inconspicu-
ous. They fly and bite only during the day.
The larvae of this species have been found in
an old pot and tin cans at Robert Dixon's; in cans on rub-
bish ba k of Dr. Farr's; and in pans in the laboratory.
The eggs are lar7e, spined, and laid singly. The
larvae are much like Culex, but can soon be distinguished
by their large size, being over one half of an inch when full
grown. They are cannibalistic and feed upon larvae of Culex,
Anopheles, and the smaller ones of their own species. 3erkley-
1902). The adult of P. ciliata is easily recognized by
its large size and the bhnds of erect scales on the less.
P. floridense looks very much like Stegomyia, but so far
as I have observed, they fly and bite only at night. 7Teither
species are ordinarily troublesome here. Yo local breeding
places have been found.
Mosquitoes and Disease.
Malaria has been known for a 'ong time, but it is
only recently that it has been shown to be caused by a spor-
ozoan parasite, belonging to the familyy Plasmodidae, and
that it is transmitted by, and only by, Anopheline mosquitoes.
The idea that mosqu toes might spread malaria, had been sug-
gested many tines, but it was not until 1898 that Dr. Ronald
Ross, of the London School of Tr-jbical Medicine, worked out
the life history of the parasite causing "bird malaria" and
found the spores developing in the stomach o the mosquitoes.
A little late Grassi, following Ross' theory, demonstrated
the transfer of human malaria by Anopheline mosquitoes.
Since that time, it has been confirmed by7 auch a large number
of workers that there can no longer be any doubt of this fact.
Theobold'(1901) in his Monograph reports forty-
two species of Anopheles from the world. There are eleven
species found in the canal zone, at le-2st five of which car-
ry malaria. (Darlinu l,.10), but we have only three that ordin-
arily carry malaria in the United State. These are Anoph-
eles punctipennis Say., Anopheles quadrimaculatus Say., and
Anopheles crucians ;7ied. (Howard 1911), the latts- two being
hil the etiology of malaria is well understood,
few poeplo realize the importance of it. T7ey take it as
a matter of providence that every one in the South should
have it and t'-at it does not amount to much. Indeed it is
very difficult to estimate the dOnate it does. 3ut Herrick
(1903) says that malaria is responsible for more sickness
among, the white population of the South than any other dis-
ease. Howard (1907) points out that from the meager data
available, thie eath rate from malaria in the United States
amounts to fifteen per hundred thousand, ortwelve hundred
per year, and that two thirds of this is in the South. Al-
though there arc no records available for this state, Florida,
with its semitropical climate, summer rains, and large areas
of flat lands, undoubtedly has its share. But the death
rate alone does not begin to show the importance of the di-
sease. Toward (1909) says:
"But with >r.alaria perhaps as with no other 2is-
ease, does the death rate "ail to indicate the real loss
from the real economic point of vies. A man may suffer
from malaria throughout the greater part of his life, and
his productive capacity may be reduced from fifty to seven-
ty fiv. pjr cent, and yet ultimately he ray die from some
entirely different immediate cause. In fact, the predis-
position to death front other causes brought about, by malaria
is so marked th t if, in th3 collection of vital statistics
it were possible to ascribe the real influences upon mortal-
ity that malaria possesses, this disease would havy. a very
high rank in mortality tables. Writing of tropical condi-
tions, Sir Patrick Manson decides that malaria causes more
deaths, and more predisposition to death by producing ca-
chetic states predisposing to other affections, than all
the other parasites affecting.mankind together. Moreover,
it has been shown that the nvera'o life of the worker in
malaria places is shorter than that infant mortality high-
er than in h1althyplaces."
Malaria is. undoubtedly the most prevalent disease
amon- t'e students. The records of the University Infirm-
ary show that for the present scholastic yea (up to May 5,)
there were a total of seventy-two cases trea ed in the in-
firmary, thirty-one of which were for malaria. This is in
spite of the fact tha'. their. is a strong' aversion among the
students of going to the infirmary and that, only the more
serious cases were recorded. The records show that the
time spent in the infirmary for treatment varies from one
to ten days, with an average of three and one tenth, or a
total for the year of ninety-six. But, as pointed out
above, these records do not begin to show the loss of effi-
ciency among the students which is much higher than is shown
by these bare records.
We have only to turn the pages of history to see
how fatal an epidemic of yellow fever may be. In 1773,
Philadelphia was nearly wiped from the map: In 1853, there
was a severe epidemic throughout the South, New Orleans
alone having a mortality of eight thousand. In 1878 an-
other severe epidemic swept this region, and spread up tie
Mississippi Valley, causing twelve thousand deaths. In
1892 there were one hundred and ninety-two deaths at Pensa-
cola, and more recently there was an outbreak in 1905 in
which nearly one thousand lives were lost. It was clearly
demonstrated by Reed, Carroll, Lazear, and Agromonte, a
Board appointed by the Surgeon General of the United States
Army to investigate this disease, that yellow fever is car-
ried by a mosquito, Stegomyia calopus. The work done in
the r cent epidemic in 1905 shows that an epidemic can be
stamped out by destroying these mosquitoes.
We have Stegomyia present in large enough numbers
to cause trouble should an epidemic break out. It have
killed as many as a half dozen in the laboratory in one
afternoon and for a w' ile during the fall of 1911, they were
very troublesome during the day at the Experiment Station.
At present, there is no danger from them because we have no
cases present to start an epidemic, but it may be introduced
into Florida ports at any time, and this will be especially
true with the increased trade incident to the opening of the
Dengue fwver is another mosquito borne disease
that is of increasing importance. Dr. J. H. Hodges, local
agentof the State Board of Health, estimates that there
were five thousand cases in this county alone last year.
While this estimate is probably too high, it shows that
this disease must be reckoned with in the future,
Natural Enemies of Mosquitoes.
Some adult mosquitoes are destroyed by birds,
bats, dragon-flies, and other predaceous insects but their
number is comparatively small.
A small mite determined by Dr. Nathan Banks as
a Hydrachind, close to the genus Thyas, has been found par-
asitic on the body of Anopheles. During October and Nove,-
ber, it was found attached to ten to fifteen per cent of
the Anopheles caught, but never in a single instance to
Culex. As many as eight and ten have been counted attach-
ed to the thorax and abdomen of some individuals, but it
is doubtful if any are killed by them.
The larvae are more easily preyed upon and we
have some enemies that are very effective in holding them
in check. There are a few waterbeetles, especially in the
sinks, that feed upon the larvae. This community is a
regular paradise for dragon flies and there are from fifty
to seventy five species found. Anywhere around the grounds
on a quiet day, you can see scores of them. Their larvae
feed upon mosquito larvae and being present in such large
numbers devour many of them. Two well grown dragonfly lar-
vae have eaten thirty-five Culex larvae ovdr night. Dragon
fly larvae have been found in the larger areas of water in
all the marshes surrounding the University, but have not
been found in the sink holes.
The most active enemies* we have are the little
*Determined by Dr. H. S. Davis.
top minnows (Gambusia affinis) (Fig.22) and the "goggle-
eye" or a warmouth perch, (Chaenobryttus gulosus) (Fig.23)
The usefulness of the top minnows have been mentioned by
other writers (Howard 1902. Van Dine 1906). It is surpris-
ing how many mosquito larvae these little fellows will eat.
A half dozen of them have eaten over a hundred Culex larvae
in a couple of hours, and ten of them have eaten two hund-
red (all that was fed them) larvae for several days in
succession. They are very active and you only have to stand
quietly on the bank to see them as they patrol the water
every few minutes. They have b en found in the deeper por-
tions of all the marshes, the sink holes, ditches, and
wherever there is a permanent supply of water. Their small
size enables them to go almostpeverwhere and to work their
way in among the vegetation. Wherever you find them is a
poor place to look for mosquitoes. They have been found
in only one instance in the same pond with mosquitoes. This
was in a circular depression coveting four or five acres,
lying about a mile northwest of the University. It is shal-
low and the slope from the bank toward the center is very
gradual. It is overgrown with water weeds and in some places,
the edges are surrounded with sphagnum moss. Anopheles
larvae were found abundant in some places among th se weeds
and moss. In some casc:s, the weeds and -oss were so thick
that you could not se- the water at all and it looked as
though the larvae were actually resting upon the moss. The
minnows were all about the edges but in some places the
the vegetation was too thick for even them. Wherever a lit-
tle open water. was found, there were minnows but no mos-
quitoes' larvae. They are very hardy and are entirely cap-
able of frecin: and keeping free from mosquitoes, ant area
of permanent water.
They could be very readily introduced into any
ponds or aquariams that are not already stocked with fish
of some kind. They are viviparous and breed all the year,
and only a few would be necessary for a start.
'n the sink holes we have also the "goggle eye"
which is predacous upon mosquito larvae. Four of those ate
two hundred full grown larvae- and ten Cambusia in four hours.
Another record shows that they ate one hundred and fifty
CuleX and thirty five Gambusia within forty-eight hours, and
still another that they ate three hundred culex in one hour.
The sinks are well stocked with them. I have several times
caught fifteen or twenty in an hour with a hook ind line.
In about one hundred specimens caught, this was the only
species found. They do not seem to prey upon Gambusia na-
turally for both are found abundant in the same sink. It
was very fascinating to watch one of these fish six inches
long chase a tiny wriggler. They seem very harjy ana can
be kept in an aquarium without much trouble. These and
Gambusia keep the sink holes entirely free. I have
ca' fully examined tho. ncvo.-al times during the ysar, and
have never found sint le larva.
Preventives and Remedies for mosquitoes.
This subject is naturally divided into two parts,
Preventives for (1) Adults and (2) Larva. There are end-
less protective fluids that have been recommended for pro-
tection from the bite of the adult. These usually contain
some essential oil such as oil of citronella, castor oil,
pennyroyal oil, kerosene, oil of tar, etc., and many are un-
doubtedly repellant to mosquitoes. But all of then are more
or less disagreeable to use and have to be frequently renew-
ed to be effective, and all in all they are a poor makeshift.
Screens and canopies afford great protection, but
they have the disadvantage of not being portable, and as or-
dinarily used, do not keep out all of the mosquitoes. Com-
plaints have frequently been made to me by students that the
mosquitoes were so thick: in the dormitory that they could
neither study nor sleep in peace. Examination of the rooms
in Thomas Hall have shovn as 4i!h as thirty mosquitoes pre-
sent, ten of Ahich were Anoph .ls (crucians and aqundrimacul-
atus) This is in spite of the fact that the dormitories
have as good screens as money can buy and it shows how' hard
it is to keep mosquitoes out if 'the are preGent.
Smudges of almost any material that would give a
dense smoke, have been used and will no doubt keep :adults
away if the smoke is thick enough, should anyone prefer to
be suffocated rather than bitten to death.
Fumijants will quickly rid a housed of the pests
and are very useful in some instances. Sulphur dioxide, made
by burnin- two pounds of sulphur par thousand cubic feet,
has boen the standard in the pa t and is absolutely reliable
but it is objectionable to use on account of its injurious
effect upon household goods. Pyrofume, a product obtained
from the fractional distillation of pine wood, s ems to be
as effective as sulphur dioxide nd less objectionable to
use. (Francis 1906.) Mimms culcicide, -ade by mixing
equal parts by weight -of melted carbolic acid crystals and
camphor gum and used at ths rate of four ounces per thous-
and cubic feet, is entirely satisfactory, but it is 3xpens-
ive. In experiments conducted by the writer, it killed all
the Culex quinquefasciatus which were confined in the room
in a battery jar covered with cloth, It is much easier to
use and not so injurious s sulphur dioxide. Tobacco smoke
will quickly kill mosquitoes confined in a tight receptacle.
As tobacco is so universally distributed and cheap, it would
be very convenient to use if it would form an effective
fumigant. In experiments conducted by the writer, the great
difficulty was in burning it so as to make a smoke. When al-
cohol or saltpeter was mixed in sufficient quantities to burn
it, it would burn without making much smoke and -was not ef-
fective when burned in a tight room at the rate of two ounces
per thousand cubic feet. It is believed that if some device
for burning tobacco so as to make a dense smoke can be pcr-
fected, it will for- a cheap and efficient fumigant. It is
believed that a device somewhat like the "smoker" used for
be -s could be used successfully.
.. :*. : .- : . : .
*. . : . .
.. .*.. .:...:
Tobacco decoction (containing about two and two-
thirds per cent nicotine) was tried in a tight room contain-
ing about seven hundred cubic feet of space. Twenty five
cubic centimeters wer evaporated over a gas burner and one
hundred and four Culex quinquefasciatus exposed to the fumes
for thirty minutes. All of them were stupified but w' en re-
moved to fresh air, about seventy five percent revived. An-
other experiment was made in which ninety five cubic centi-
meters were evaporated in the same room and about fifty Culex
quinquefasciatus exposed to tte fumes for one hour. None of
them in this experiment were killed. Some trouble was found
in evaporating this much of the decoction as it forms a
thick syrupy mass and vaporized slowly. It is thought that
that "Black Leaf 40" which contains forty percent of nico-
tine sulphate can be used to much better adv ntage, but none
was available for experiment. As it contains about fifteen
times as much nicotine per volume as the other decoction,
probably no difficulty will be experienced in evaporating
a sufficient quantity to kill them if it proves effective.
Oil of turpentine was tried as a fumigant, but it
caught on fire so the experiment was discontinued. It burn-
ed with a dense smoke which completely filled the room but
did not .kill the mosquitoes. It is important that the evap-
orating vessel in all fumi ants, be placed near the floor
as the fumes are lighter than air and otherwise the mosquit-
oes near the floor will not be harmed.
Green camphor leaves were dried in an oven and
burned at the rate of two ounces per seven hundred feet,
were not effective.
Remedies Against Larvae.
Preventive and remedial work against the adults
is desirable and often very effective, but it is onl- tem-
porary and does not destroy the root of the troubles. It is
better in all cases where it is possible to either kill the
larvae or to destroy or render uninhabitable thP breeding
places, and it is more saitsfactory and usually cheaper in
the long run to destroy the breeding places. The peculiar
habits and structure of the larvae make it possible bo kill
the-i rather easily, --ith substances called larvicidess"
These substances float on the surface, forming a film which
prevents the larvae from reaching the air with their anal
tubes. Various substances hav-e been tried and many have
given good results, but sonsidering everything, petroleum
products have proved the most satisfactory. It was suggest-
ed as early as 1812 that kerosene was effective in killing
larvae, but the use of it' did not become very general until
about 1895. Since then i'; has been used in numerous cases
with good results. 7-. E. 'Need rid the campus of the Mississ-
ippi Agricultural College of mosquitoes by oiling eleven
water tanks. Prof. H. E. Kellogg found that by po-mring
a little kerosene in some cost holes that the m- squito plague
was almost i'-mediately alleveiated a Leland Stanford Uni-
versity. Mr. W. C. Kerr did some large scale work on ponds
and swamps on Staten Island and Dr. J. 3. Smith reports
its successful use in two cases on Long Island. An oil
suitable for this work should be light enough to spread rap-
idly and yet heavy enough not to evaporate too readily.
A low grade oil known as fuel oil has be n found best suited
for this. Lir. H. J. Quayle (1906) used a mixture of a
heavy ;ighteen degree Baume oil and a light thirty four
degree 3aume oil in some pool and creek beds that could not
be drained :asily, with good success. He found this to be
efficient from one to four weeks, depending upon the nature
of theft pond and the exposure to the wind. To bJ on the safe
side, the pond should usually be oiled every two weeks.
Te used a barrel spray pump in the accessible places and a
knapsack pump in the others to goof advantage; but it may
be simply poured on from a sprinkler or applied from a bucket
with a mop. In inaccessible swamps, it is s-metimes ap-
plied by standing barrel on end and boring a small hole
near the bottom so there will be a constant drip.
In th1 Panama Canal work there w s considerable
difficulty in getting the oil to completely cover the sur-
face when the vegetation was thick. There they found a so-
lution made from one hundred and fifty pounds of sulphuric
acid, on, hundred and fifty pounds o- orderedd resin, and
thirty pounds of caustic potash boiled together made a good
larvaecide, (Gorg,-s 1909) and to be more 3ffcctive in some
cases than fuel oil.
A pool on the campus between Buckman and Science
Halls, and the cesspool back of Thomas Hall, have b on treat-
ed with "Zenoleum" disinfectant twice. This forms a milky
mixture with the Tater and kills thn larvae in a short time.
Both pupae and larvae were found alive four hours after ap-
plication, but all were dead next morning. No record was
obtained of how much was applied, but enough to make the water
decidedly milky. It was fond to prevent ogg laying for a-
bout twelve days, and should be applied about every two weeks
to make ther- safe.
Ordinary kerosene is cormonly used when only small
areas are to be oiled. Tt is more expansive than crude oil
and not any 7ore effective. Any system of oiling has to be
done every few weeks during the year, which in the long run,
proves expensive. It is cheaper after all to drain the breed-
ing places as they then require very little attention.
Drainage hes been becoming more popular in recent
years and large areas that it would have been thought fool-
ish to attempt to drain a few years ago, have been success-
fully drained. Perhaps the most extensive work has been done
in the New Jersey marshes by Dr. J. B. Smith (Smith 1901-1911)
The salt marsh mosquitoes which develop here are long dist-
ance flyers (forty miles in some cases) and large areas had
to be drained to control them. Something of the magnitude
of tte work in general is gathered from the following figures.
Up to 1911, about thirty-thousand acres had been drained and
nearly four million feet of ditches dug at a cost of about
s'75,000 (Smith 1911). Wherever this work has beon done,
the mosquitoes are practically eliminated and it has proved
successful in every way. This work has been accompanied by
considerably oiling, is is usually the case, to give i(me-
diate relief and in some places thjt it was not pracoticable
Numerous other cases are on record of the eradi-
cation of these mests and the disease s they ca. ry, by these
remedial -easures. Prior to 1905, a house to house inspec-
tion showed that twenty per cent of the population in some
parts of Gta e Island were suffering from malaria. Ant.i-
malaria work was undertaken and in 1909, there were only
five cases of malaria reported (Howard 1910) Dr. E. P. Felt,
(1905) states that Lawrence, Long Island, has been freed
from the salt marsh mosquitoes. H. J. Quayle (1:-06) reports
some very satisfactory work against the salt marsh mosquito
near San F:.ancisco. Th: Lawrence, L. I. 3oard of TH-calth
(1903) has done some good work which has rid their town.
Havana, Cuba, has been cleared of yellow fever and made
habitable by anti-mo:--uito work done under direction of the
United States Medical Army Corps. The spidemic of yellow
fever in New 0.leans in 1905 was stamped out by clearing the
city of mosquitoes. Some o the most successful, as well as
the most difficult anitmalarial work, has be .n done in the
Panama Canal Zone. Under the French administration this was
a veritable death trap. The tales told of the deaths are al-
most unbelievable, in fact it was difficult to keep enough
men there to keep records. When the Americans took charge, the
first thin-, done ws to organize a Depratrent of Sanitation to
clear the zone of mosquitoes and fever. TI'is has been so success-
ful that it is now considered a health resort. Their hospital
reports show (Gorgas 1913) that their monthly average. of cases sern
to the hospital for malaria was only ninety-two hundredths of one
per cent of the entire force, n.hile similar records at the Univer- ty
show ten per cent.
These facts le rTe \us no room for doubt as to the
efficiency of these methods. If Staten Island and Long Island,
surrounded by water; if New Jersey with her thousands of acres of
marsh and mosquitoes flying forty miles; and Panama with her trop-
ical rains and with excavations made by buildings, can be freed
from mosquitoes and malaria, why can't the University of Florida?
It can. In fact it would be an easy matter to destroy the breed-
How the 7,ork at the University Can be Done
As pointed out before, all of the species and
breeding places found are entirely local. In other -ords, we raise
our own supply and are bothered only by home grown mosquitoes.
During the past year, I have carefully watched for the breeding
places and, they have already been pointed out. Duri-g t'e present
year a good start has been made toward ridding the University of
mosquitoes by the company owning UTniversity Place. They have put
down altogether about a mile of sewer (Fig. 24) at a cost of four-
teen hundred dollars, and have spent thirteen hundred dollars in
grading and filling. This work was not undertaken primarily for
anti-mosquito work anc h-s been much more elaborate and expensive
than w-.s needed for this purpose. This area, containing four or
five acres, was formerly as bad a marsh and sup lied as many mos-
quitoes as any breeding place we had to deal with. They have tho-
roughly drained it and now it is as safe as nay place aro-.nd the U-
niversity, furnishing desirable building' lots. (Fi:s.25 and 26
show this place before and after this work was done. I have talk-
ed with the residents living along University Avenue in this sec-
'ion, and the-7 say that whereas before this was done the mosqui-
toes were very troublesome, now they can sit on the porch in comfort
The marsh lying on the north of us is not on the
University property, but I have no doubt that the owners would cive
their consent, and probably their support, in ditching this. It
would -reatly increase the value of this property and, as nearly
all of it is in the 'ands of real estate people for 'ale, they
would doubtless cooperate, especially when they see what has been
accomplished in University Place. This area need not be tiled.
A central ditch extending from a point north of Science Mall to
where !hi.: channel joins a larger stream, would not require over
three fourths of a mile of ditch. There is a channel extending
over this entire length now and 11 that is necessary would be to
deepen this and remove the obstructions in -iany places while in
others, distance could be saved by cutting a new channel. This
ditch need not be over two and a half feet wide, an'd as the fall
is not very ;reat it would have to be shallow. The east end of the
marsh extending westward as far -s the road leading to the iArnold
place, should be cleared of under brush an2 lateral ditches cut
where necessary. It is not wide and not more than five hundred
yards of lateral ditches would be needed. A few pools along the
side should be filled in but there would be very little filling
required. The small holes which could be found after the under-
brush is cleared out would` not be any trouble to deal with.
Clearing up the marsh for thi" distance would establish a z,-ne of
safety or this side, for it has been shown time and tine again
that the species usually found here fly only short distances.
In Panama, a zone only three hundred yards wide giv:s them pro-
tection a ainst Anopheles.
The well and premises of Robert Dixon, which have
been such a prolific s-urce, could 'e easily cleaned up. For
less than "5, his well o"uld be covered and a pump put in, and he
would empty the water in his vessels once a week if someone -ointed
out the importance to him. Some >f the rubbish pile near here
has '-lready been removed and it would be an easy matter to remove
th rest of the cans or turn then upside down.
Language Hall will soon be completed and all the
holes around here filled in. As soon as other building s are begun,
they will h,-ve to be watched, but it would not be expensive to oil
any standing water once a week. There a -e no deep holes in this
part of the campus. The grass should be cu' close so it will be
-ossible to se the small depressions, wayon ruts,-etc. They are
all small and A, few wa"on loads of nd would fill them. Better
outlets for t'-e road ditches could be secured by ext -nding them
on to the corner of University Place. A pipe has alreadyy beon laid
from the side ditches along the Ocala road and connects with the
the -ewer. A wa-on load of oand would fill up the pool b'e-
tween Science and ,3uckman Tals. The ce spool in this vicin-
ity is covered with dirt and is safe. The eastern portion
of the campuss should be kept clear of -eeds and in a neat
condition, so that a man could be sent over it on e in a
while to report anyr puddles th.-t had b- n formed.
We have no breeding places on the south to fear
On the west, we hve the mars- back of the '-itchen.
This area is small and has a -ood -all and could be e ssil
drained. In fact, if the -,eve-rs from the Univers;ity were
extended -rom the buildin-" a respect-ble distance, it would
re"-ire very little 0 aina-e. Th3 underbrush s would be clear-
ed out and if the i ench extending up toward the 'e- all
.were opened u) and the ewer- extended down to the main ditch,
there -ould be very little else to do. There are only a few
breedin- -olaces scattered through here. Cl0arin- out the
brush anCd weeds is i-'ort-nt for it is next to impos.-ible
to find all the holes unless this is done. This "rea would
make a very nice -adition to t'-e campus if 't -were -rained
and clenr d out.
'he Dessnools back of Thomas T-all could be covered
with a screen or a covering of matched boards and made mo'-
We should have a general clearing up of the campus
and remove all the rubbish, etc., that may be likel-- to hold
water. The drain pipes in the '-semen-s -here water stands,
should be opened or the water oiled.
I wish to especially emphasize the importance of
the small breeding places. Our whole supply comes from such
sources. It is l-'ost incredible how nany a small place will
breed. Lugger (1896) has be filt-ring the water -'nd actually
count of portions of it, found nineteen thousand, one hl-ndred
and ten eggs, larv-o, and pupae in one barrel. And when we
consider that one barrel may easily mature fifteen to twenty
broods a year, -e see what an amazing number mayr come from a
small area. It also sho s how futile it would be to drain
the larger areas and neglect the smaller ones, and how im-
p-ssible it would be to eliminate the mosquitoes from the
Universit- nlees t, w-ork -:as ha'-en up in ea careful, sys-
tematic 'way qnn thoroughly done. The man in charge of the
campus should be in sympath-7 with the work; should know the
habits of the species cnd know the details and the iumport-
ance of the. details, in eradication. The eradicatio- of
mosquitoes from the campus is not a difficult task, b-.t it
means ,ratchfulnes:s of the sall puddles and the general san-
itary conditions. There a e no de p fills 'o be made, or
larS r-s-a to b-- drained, so the *-.ork would not be very ex-
bensive. 7ive hundred dollars judiciously spent would so
effectively reduce the number of mosquitoes to ren .er them
unnoxious and it see-'s as if the University could well spend
this small amount for the increased ;omfort and health it
would afford t".e students.
An Ac.:ount of Experiments Jonducted -7ith -"raps
.For -dult MTosnuitoes.
During the summer of 1912, Dr. E. W. Berger called
my attention to a trap t'at 7I. Maxwell Lefroy (1907) had
used for adult mosquitoes in India. No work of this nature
had b.en done in the Tnit.d States so the writer took up the
work Septenber 1st., The object was to deter.in-e if they
could be used successful in freein- a dwelling fro': nos-
nuitoes and to det rmiane tl-e abundance of mosquitoes during
the different w-onths of the yrar.
Dr. 3er -r used the traps during- June and pa t
of July and has kin ly placed his records at my disposal
and I am otherwise indebted to hin for -an su:-e tions nade
during the year.
ThF. traps used are simplified forms of those used
by Lefroy and consist of a "ark v ssel or box of some kind.
A success f 1 style used was a )lain eart'ern ware jar or
crock (Fig. 27) commonly called a churn, si-: to ei7ht inches
in diameter, sixt'en to -ifteen inches high with a capacity
of two to three -.llons. They are -rey colored outside and
dark chocolate brown to black within. imnother forr. of crock
used (Fi 28) was ten inches in diaret-r an" t-relve inches
high. Several shapes and sized of boxes were used (FiL 29)
A box seven by seven inches square and thirteen inches deeo
gave results. Smaller and larger sizes were used. The
Boxes can be constructed of an-r material th t can be made
fairly air- i-ht. In zact, all of the boxes used were pick-
ed up around the ''xperiment Station. It is usually neces-
ary to reverse the opening found in the ordinary box, i.e.
nail up the side usually op ned, the long way of the box,-
and use one end for the top. Cracks or crevices should be
tightly stuffed or the mosquitoes will hide near them .-d be
difficult to kill. Some of the boxes were painted green
inside; some werepaintel black; some were lined with green
cloth; some were lined with black cloth; an!' others were
left the natural color of the wood.
A jo-int of six-inch stove pipe was also used suc-
cessfully. A piece of cloth wa s tied securely around one
end for s bottom, and another piece used to conf-ine the nos-
Large gallon bottles, having an inch to one and
a half inch mout'" were painted green an(c black and tried,
but did not live satisfactory results, and were soon dis-
continued. In fact, their w:as never a single specimen taken
from the e bottles.
These traps were placed in the different positions
described in detail later on and were left uncovered during
the night so the mosquitoes could settle in them. They
were covered from seven to seven thirty in the 'morning be-
fore the sun reached them. Then approaching the trap, the
cover should be held in readiness to nuic'ly place over it,
otherwise the mosquitoes will be disturbed and arise at your
approach. It s very often noticed thst several '- t had
alight,;d n'.r the top of the trap, would fly away at my ap-
proach. Anything thC.t -ill completely cover the trap and be
comparatively airtight, can be used for a cover. A piece -f
cardboard or several thicknesses of newspaper covered b-y a
board to prevent disturbance by t e wind, was fo nd satisfact-
ory for the boxes, an' a piece of cloth la ga enough to tie
over the otove ?ipe was all that was needed. A very conven-
ient cover (Fi3'. 30) for both corocks and boxes was a frame
made like those used for box heads, covered with wire -uze.
A cardboard or newspaper :ras cut to fit the inside and a brick
used to hold it do-.m. This style allows an examination of
the contents and is very convenient in adding the killing fluid
which can be done without removing it, while with other styles,
one corner has to be opened.
Gasoline was found the cheapest and most effective
killing agent. Carbon-bisulphide left a disagreeable odor,
and deposit of sulphur and c loroform or ether *-s to ex-
pensive. .-en the trap is covered in th.e morning, gasoline
was added at th rate of half a teaspoonful per allon ca-
pacity of the crock and two or three tim s as muc" for the
boxes and Ctove pipe. If t'e boxes are not mac(e tight, many
will not be -ill.-d with this dosage for they very cunnln-'ly
hide by the cracks where the frerh air comes in. More gaso-
line was needed o, a windy day than a still one, and more in
winter than summer. It is important to a- just enough gaso-
line, especially in the crocks, If too little is used, they
will not '-e killed. If too much is added, .t ,-ill not all
evaporate and the specimens falling into it become wet and
draggled and dry in all kinds of shapes, which makes deter-
minations difficult. This would not be objectionable unless
the specimens were kept for later study. The bottoms of the
boxes absorb d any excess of gasoline that was added nrd al-
ways Zove nice dry material.-
A pint of boiling water poured into the rocks was
ajpo effective, but could not be used for the boxes. As the
water does not give good specimens for determination, I found
it more convenient to ue gasoline. Fifteen or twenty minutes
is sufficient time to leave the crocks covered, but in my case
it was more convenient to leave then until two or two thirty
in the afternoon. They were removed and each day's catch at
Bergers' and Shaw's kept separate. Sixty per cent alcohol
with two or three percent formaline was tried as a preserva-
tive. Specimens in this fluid soon faded out as the scale
structure is always hard to make out in wet specimens, it was
discontinued. Small vials fitted with corks were next tried,
but as the specimens were often times damp and ful! of blood,
they would soon mold. Cork stoppers were discarded for cotton
olugs and the. e gave better satisfaction. Later ITo. 32 pill
boxes were substituted 'nd these ,ere found more convenient
"The active principle" of these traps consists of
their appeal to tbe light reactions of mosquitoes. They are
phototactic up to a certain degree of intensity of light -nd
negati-ely phototactic after this is passed. This was fre-
quently shown in the laboratory. DurinZ the day if the con-
fining jar was placed so th:;t one side was darker than the
other, they would collect on.the dark side. Towards dusk,
when the light became less intense, they would collect on
the side toward the light. The would also collect on tLo
side nearer the electric light at night. It is also known
that mosquitoes settle on dark colored walls ?rnd objects much
more readily than on light. If there are only a few mosquitoes
in a room, the-r are usually to be found in the darker areas
of the wall an( in closets, bookcases, dark corners, etc.,
during the day. Advantage can well be taken of this by open-
ing the windows between sundown and dusk and disturbing their
hiding places with a duster, towel, etc. The mosquitoes will
fly toward the light and out of the open window and in this
way the number in t',e room can h:- -reatly reduced.
Size and Shape of the Traps.
The size and shape of the traps affect the catch,
only as they affect the light within the trap, for as pointed
out above, the mosquito-s enter the trap to secure a dark
place to hide in and a trap to attract them must necessarily
furnish this condition. This is best secured in a small deep
shape. In some of the preliminary work, a small deep box
about six inches deep was tri-d alongside of a box the same
size but fourteen inches deep. It did not give -ood results
and was soon discontinued. It gave better results when
half of the opening was covered by a nao ine so that the
light did not reach the bottom so readily. A very convenient
size box was found to be seven inches square by fourteen inches
deep and a crock that gave 7ood results was six inches in
diameter and twelve inches deep. In any case, the depth
should be about twice the width or the diameter.
Position of the Traps.
This is very important and upon it depends their
success or failure. The traps used ,were situated upon the
porch of Dr. B-r er's house, just east of the campus in Uni-
versity Place, and on the porch of .r. 0. H. Shaw's at the
Pepper house, situated at the north west of the campus.
Dr. Ber' r's house faces west, with the porch extending all
#he was across the front. The :-o- dwork is painted 'ark -reen
and the porch has a solid coping around it and at light trellis
at either end which were up part of the time and down part
of the time, but they were never covered with a dense growth
of vines and did not noticeably affect the catch. There are
two double windows and a door opening onto it. These and the
location of the traps are shown in the diagram (Fig. 31.)
The traps were located on the so'th end nex' the ,all (S E, b,o),
near the coping (S W: bo ), and midway between the two. On
the north end they were situated on the saE~t side hear the
wall (N E; b, b )
Mr. Shaw's house fac : south, with a front norch
and a porch on part of the east side. There are two and a
door opening on the front porch, and two windows on the ea t
side. There is a corner about two feet ea:t of the door that
projects out -ard a couple of feet, There is a rather dense
trellis work of wisteria on part of the front porch and
part of the side porch. The traps were locatedd at the right
and left sides of the door (D; r, 1 ), at the window on the
front porch (south) (W; b, b ), and at the north end near the
window (N; c, b ) (See diagram Fig. 31 )
Traps were also situated on the back porch of Mr.
C. K. McQuarriefs, in a bedroom at Dr. Berger's, in bathroom
and halwvay of Bucklcan T all, in the Experiment Station toile-f
and at a residence down town, but records for short tine only
.:ere secured at these .places.
The importance of the position is strikingly shown
by Table 1, giving the records of two crocks located on Dr.
Bera her's porch. They were exactly alike and received the
same treatment, except that one was situated on the south end
next the vall (S E ; c) and other not eight feet away near
the coping (. 0; c,) The table -ives the average number
caught p r night for five and six months (October to March.
T ere being no record for the ,rock situated near
coping (S W; c.) during November, this is for a five month
Table 1. The effect of position upon the number of mosquitoes
Position of Crock, Months recorded, Average caught
Dr. Berger's at S E:6 6 21.2
Dr. Berger's at S.W:c 5 11.3
This large difference in the number caught can be
explained as follows: As the day breaks in the morning, the
outer edge of the porch naturally becomes lighter first.
This causes the mosquitoes to retreat toward the darker side,
which is next to the green colored wall, and they settle in
This tendency to go toward the darker side is also
shown at the Shaw's porch near the door. Here a crock was
set on one side of the door and a joint of ntove pipe on the
other. The one or the right has given the large t catch
throughout the winter. Some records for ten nights during
March show that when the crock was on the right, it caught on
the average 1.56 times as many as the stovepipe and that when
the tove pipe was on the right, it caught 1.47 times as much
as the crock, showing that which ever one was on the right,
always caught the most. This is in spite of the fact that
either a s3all table for holding flowers, or a box used for
umbrellas, etc., was always found on the right in 'he corner
next the wall and a large number of mosquitoes settled under
the t ble or in tho box.
Th: conditions are somewhat similar to those found
at Dr. 2erger's. There is a projecting wall (see diagram) to
the right of the door that cuts off the early light, leaving
the's a darkened corner. The vines which are rather thick on
this side of the porch, also end at a potnt at point about
opposite the right side of the door and the7 .ut off some of the
light an the right but do not affect the left so much.
The effect of having large dart places near a trap
was well shown on a small north east porch at Mr. MoQuarries,
The porch is latticed, but not screened and mosquitoes were
plentiful. A trap was tried here and gave very poor results,
while a large dark cupboard would contain hundreds. The norch
is small, but the trap situated near the cupboard, in the cup-
board, or on the opposite side of the porch, alwa-s gave poor
In a bedroom at Dr. Berber's, where the walls and
furniture are stained light, and where there are no dark
closets or corners, for them to hide in, he could catch four or
five, and at one time a dozen, when they were not numerous
enough in the room to be annoying. In th, dormitory where the
woodwork !i stained dark, and there are closets, L.okcasc.,
etc., I could catch but a few or none when they were too nu-
merous for comfort.
In the toilet in the third floor of the Experiment
Station, traps also gave good results. The room is small and
with few dark places. Two small traps situated here several
times contained about twenty specimens each.
The effect of light was also shown by the number
found on the window screens. The window scree- over the win-
dow on the front -;orch at Shaw's (W fig.) would invariably
have a number of mosquitoes resting there, sometimes very thick
as over t.o hundred have been counted here at once. This screen
is behine the thick part of the vines and always dimly lighted.
The other screens are not so well protected and never contain-
ed but few, or none, although sometimes found in abundance
behind the shutter. At Dr. Berger's where there is no protec-
tion at all, not a single specimen was ever found resting on
While the position is -very important, it is some-
times hard to tell by looking nt a porch or room, just where
the best position would be and it is usually dell to try a
trap at several points to determine which sives the largest
The Effect of Color
And Cloth Linin. in the Boxes.
The only colors tried 'ere black, green, and dirty
greyish, the natural color of weathor-beaten wood. One box
was painted black and one lined with black cloth. One was
painted 7reen and one lined with Zreen cloth, while another
w s left the natural color of the wood. (The two green
boxes were practically the same size 8X8X15, while the cloth
box was 7X7-Xl3, and the black painted and wood were 6X6X12)
Table II.-The effect of color and cloth lining in the boxes.
Kind of traps Position of Trap Time re- Average
corded. Number Caught
Green Paint Box Berger's Feb. to April 5.9
Black Paint Box Bergerls Feb. to April 11.9
Green Clot, 3ox Shaw's Feb.18 to Mar.21 73.3
Black Cloth Box Shaw's Feb.18 to MLar.21163.5
Wood Box Shaw's Feb.18 to Mar.21 31.9
M]rom the data secured no definite conclusions can
be drawn ,as to the effect of color alone. The black painted
box at Dr. Berger's caught (average for February to April)
twice as many .as the green painted box. The green cloth
at Shaw's caught 1.2 times as many as the black cloth
(average February 18th to March 21st.), and 2.3 times as mania,
as the wood box. Thus it is seen that the black painted box
gave more than the green paint, while the green cloth gave more
than the black cloth, and that both the cloth lined boxes gave
more than twice as many as the wood.
Boxes lined with cloth seem to be more satisfactory
an the whole than either wood or paint. The cloth or paint
should be of a lark green or block color, or otherwise it will
reflect the liZht and nake the interior of the box lighter.
This probably accounts for some Vf the low -atches in th green
painted box at merger's, for the box itself is slightly larg-
er than the black, and the paint used was not a very deep green.
Effect of Wind on the Number CaugAt.
The direction of the wind is very variable. It may
come, and usually does, froni any quarter. No data was secur-
ed as to the relation between the direction vf the wind and
the number caught, but from observation, 4t appears to have
The velocity of the wind does affect the catch. On
a still night, the catch was always higher than on a windy,
but as a high wind is usually accompanied by a- drop in tem-
perature, this accounts for 7-ost of the difference. It was
noticed that mosquiotes were very loath to leave their hiding
places on windy days. 7hen they were disturbed by wal king
through the vegetation in the marshes, they would almost im-
mediately drop down again and evidently do not enj-y being
blown by the wind. They were also much harder to dislodge
from their resting positions on the screen at shaw's when it
Effect of Teiiperature on the Number Caught.
The effect of temperature was observed throughout
the winter, warm still nights always giving a larger catch
than cold nights. The curve in Fig. 32, shows the variations
in temperature and the number caught in the green cloth box
at Shaw's for the month of February and shows the close corre-
lation between the two.
As we had some of the coldest weaterh of the win-
t"r during February, the temper ture was very variable and
the correlation between the number caught and the temperature
nay be closer than for some months when the temperature was
more .iniform. Mosquitoes like all other insects do not de-
velop as fast in cold weather as in warm weather, and a few
days of cold weather -nuld retard the larval and pupal devel-
opment and the minerence of the adults. But as the adults
live several w eks we would have those present that had de-
veloped in the previous warm spell and this would not account
for the sudden decrease. A drop in temperature probably
causes the same reactions as it does in the fall of the year
in states farther north when it causes them to go into hiber-
nation and this results in them remaining in their hidin-
Attractions Used in Traps.
Mosquitoes are very fond of fresh fruit. They hlve
been observe d feeding on sever-'al kinds of fruit and they seem
to be especially fond of guavas. So different kinds of fruit,
apples, bananas, and zuavas were placed in the traps with the
hope that they would be attracted by them. Ths only increase
noted was in the number of ants and as these were very trouble-
some about carrying off the mosquitoes, the fruit was discon-
tinued. Raw beef wv s tried with a similar effect, in f oct,
on two or three occasions, the beef would smell rather offen-
sive by -'ornin- and the number of mosquitoes was actually de-
Urin-, banana oil, and water seemed promising at
first and were tried for longer periods. A three hundred
cubic centimeter bottle of urine was placed in the trap andc
a small vial or a little-banana oil poured on the bottom
were th3 methods used. A saucer was placed in -he bottom of
th-- tra-p or, in the case of the crocks, about half an inch of
water was poured into the bottom. Several egg boats were laid in
the traps containin~- water during the trial. Dr. Berber
seemed to get a slight increase in the number caught when wat-
er w s used, but it was tried for only a few days and s it did
not show any increase .nd Te bedraggled specimens, it was
discontinued. Later it was given a longer test.
Table III.' The Effect of Substances used in the tri-s to at-
Substance used. Trap. Date recorded. Average num-
ber caugIt .
Banana Oil GCreen Cloth Box 4/16 to 5/10 26.1
Check Wood Box 4/16 to 5/10 15.
Bottle of Urine Crock 4/29 to 5/4 15.8
Check Pipe 4/29 to 5/4 9.1
Tater Crock 4/18 to 5/10 4.7
Check Crock 4/18 to 5/10 7.7
It appears at first glance that some of the
subst nces used were attractions but a study of the table
shows otherwise. The -reen cloth box in which the bannana
oil 'Tas used was placed in the sane position as it was in
Table II were it w-.-as shown tt the green cloth box s,:ve
over twice as many as the -wood box when no oil was used,
while Table III show-s that it ve only 1.6 ti :s as nany
and th t the bannana oil was rather a repellant.
The crock in the experiment with the urine was si
uated alwa--s on the ri ht side of the d,-or, w'.ere it -ver.al
about one and six tenths tines as many as t'-e pipe on the ot her
side where no urine was used. The proportion here is very
little higher. In the test w'it' water, two similar crocks
were placed side b- side at the south nd of Der:er's porc'-,
and the conditions were as similar as could be secured. The
t ble shows that the ,war actually decreasedd the number caught.
In th. records a'tainm d from Dr. 3 rser, no check was used -
watc._' was placed in the crock one day and lf.t out one, so this
may account for the discrepancy of the results.
Repel'ants used in Tra .s.
Several -substances thnt -ave been recommended -,s
repellants for mosquitoes ,vrere tried in the tr-ps to deter-
mine the effect u-on the number caught. The method used was
to place a snall vial of the substance in tVe trap or pour a
little in t'-e button.
The most effective repellant vwas secured from
"r. "ood o' t'. U. S. Department o'f Agricultur'e, through
Dr. 73eroer. Its compositi-on is unknovmwn but it seems to be
:ade -f oil of citronella, oil of p&tti-rain (obtained from
distillation of oran-e leaves) and cerbolic acid. It has a
v ry penet -tin;; smell and a box would smell of it for a week
aftor it s -poured i- it "Sketer Skoot" is-a proprietary
compound made b- t-1he Tnited Dru'- Co. i .an- t '- proved erffect-
ive. -Bombay vapor, a product obtained b-- the fr- tonal dis-
tillation o-' wood, stood next -while 0-. of citronella stood
next the la t ith -i'l of tar. These repellants Were tried in
th,; -ren cloth -' black cloth' boxes at Shnw's, while t:-
wood bo:: was placed beside them for a ch-c'-. The rel-tive
number c..-"'t by t.ese different boxes bes been -iven before
an t ,7his as toan into con. ide_.'ation in findin- the -ercent
Table Shovn:;: effect o' repellants.
Avera e Averor-e Per-
e-pellant Trap Used T o. ichts !To.Caught No.In cent
pr.ni-ht Check I epel'd
od" Re--llant "reen Cloth '.15 1. 25.1 92.814
"ke .ter Skoot" 12ack Cloth 5 10.6 50.6 82.7
3ombay Vapor lack Cloth 5 .1.6 12.1 80. 4
0il of Citronella 'lack Cloth 10 11. 15.2 64. -
Oil of Ta .lack Cloth 10 15.2 17.0 S. M ,
These different repellanI wviere also used for a ni-ht
or two at ti'-e at oth r ti- .. nr always decreased the
catch. As 1, was desired to get some dat:. o7 the relative
nuriber of niosriuitoes present throughout the yea', the:ry 'ere
"sed for onl7 short periods. Tostin-' the efficiency of a re-
pell,-nt in a trap --ay prove useful. The con itions are 'uch
better for scurin check than when used on a person ,Tho is
apt to be movi.,- -,bout or ot'erwv.ise dirturbin- the mos-uitoes.
In a trap yo-' can t the actual number "sepell-d by comparing
wvit> t'c ch ck, while on a person yo- nevor know how many were
actu,.lly repell d.
Species C u-ht
Onl--- five Kav, 'en takenn from th.. r.p. s hse crc
as follows: *
Culex quinquefosciatus Say.
Anopkeles quadr i:aculatus .cay.
Anopheles crucians WVied.
Psorophora cialiata ?ab.
Stegomyia calopus :.,eig.
* First four were deterr.'ned by Dr. H. L. Dyer of the U. S.
3ur.eau of Entomolo*y.
Table IV.-The number of males, females, females with blood in
abdomen; females with developed overies; and the
total number caught per month at Dr. Berger's
Females Females Total
Month Males Females with blood with devel- number
in abdomen oped overies. caught.
June 1912 636 226 45 65 862
July (all 288 121 ? ? 409
Sept. 544 313 56 100 857
Oct. 759 477 114 83 1236
Nov. 180 140 43 23 320
Dec. 172 166 40 43 338
Jan.-13 451 234 38 40 685
Feb. 659 526 70 60 1185
March 851 712 128 85 1563
April. 362 300 61 60 662
May 137 135 32 50 272
Total 5039 3350 531 609 .8389
June 0 5 0 2 6
July counted with culex
Sept. 13 23 3 4 36
Oct. 1 9 0 0 10
Nov. 2 3 0 0 5
Dec. 0 6 0 0 6
Jan.-13 1 0 0 0 1
Feb. 1 0 0 0 1
Mar. 0 3 0 0 3
April 1 5 0 0 6
May 0 3 0 0 3
Total 19 52 3 6 71
June 3 5 1.2 8
July Counted with culex
Sept. 1 4 0 0 5
Oct. 3 15 4 3 18
Nov. 2 7 0 1 9
Dec. 0 1 0 0 1
Jan.-13 1 18 0 2 19
Feb. 0 6 0 1 6
March 0 3 0 0 3
April 2 12 0 0 14
May 0 0 0 0 0
Total. 12 71 5 9 83
Total for all species for year 8W_
Table V.-Number of males, females, females with blood in
abdomen; females with developed overies; and the
total number caught per month at Shaw's.
Females Females Total
Month Males Females with blood with devel- number
in abdomep oned overies caught
Sept.* 127 46 9 11 173
Oct. 856 722 67 64 1578
Nov. 479 377 42 38 856
Dec. 315 250 23 29 560
Jan. 404 311 8 15 715
Feb. 1204 753 16 17 1957
March 1753 1616 64 113 3369
April 862 566 47 81 1428
May 684 372 32 45 1056
Tdtal 6684 5013 308 413 11697
-Sept. 0 4 0 0 4
Oct. 5 9 2 0 14
Nov. 2 21 3 0 23
Dec. 2 9 0 2 11
Jan.-13 2 3 0 1 5
Feb. 0 2 0 0 2
March 4 9 0 1 13
April 3 11 0 2 14
May 0 4 0 0 4
Total 18 72 5 .6 90
Sept.* 0 0 0 0 0
Oct. 10 27 5 2 37
Nov. 2 7 0 1 9
Dec. 0 6 0 0 6
Jan.-13 0 21 1 4 21
Feb. 0 5 0 0 5
March 2 19 0 1 21
April 0 10 0 1 10
May 0 5 0 0" 5
Total 14 100 6 9 114
Total of all species for the year 11901
*Some of these were caught -t Mr. McQuarrie's.
These tables are based upon the actual number of
specimens identified in the laboratory. The actual number
caught in each month always runs higher, A daily record was
kept: of the number caught in each trap as they were removed
from the trap, btt all of the specimens from Shaw's and from
Berger's (for each day) were placed together. Some of the ma-
terial was lost in several, by destruction by ants, by
moulding, or by loss, breakage, etc., but as between ninety
and onehundred per cent were identified, this may be taken as
a fair average of the whole.
Only three Stegomyia and two Psorophora have been
takenduring the year, so these are not listed in the tables.
Tables IV and V show that less than half of the total
number caught were females, the only ones that bite. In Fig.35
the curves show the variation in percentage of the females
caught; the females with blood in the abdomen; and females with
developed ovaries, of the Culex quinquefasciatus caught during
each month. Such a small number of Anopheles were caught that
these are not given.
The percentage of females is based upon the total
number of all species caught, "he percent es of the females
with blood and well developed ovaries are based upon th total
number of females of this species. It is seen that there is
considerable variation in the percentage of females caught per
month and there is also quite a variation at Berger's and 'haw's
for the same month. The explanation is not definitely known.
Whether or not this is the relative number of males
and females found in nature, cannot be answered. It seems to
be a well attested fact (Berkley 1903) that, with the exception
of the Stegomyia, from a given lot of eggs reared artificially,
about two thirds will be males and one-third females, Dr. Ag-
ramonte (Berkley 1903) found the relation of females to males i
-in Stegomyia to be about six to one or more; sometimes the re-
verse was true. In specimens bred in the laboratory, the males
always emerged first and were usually more numerous, but not
always. In one batch of nearly grown larvae and pupae of Cu-
lex secured from th- campus and bred in the laboratory, there
were two hundred and ninety-one females and onehundred and six
males. It has been shown for many genera of insects that an
abundance of food will largely increase the percentage of fa-
males reared from a total number of eggs. (Berkley 1902)
has found this true with Anopheles.
It may be that the per centage of females caught in
the traps express approximately the percentage of females found
in nature during this time. It has been pointed out before that
the mosquitoes caught at Ber!er's and Shaw's bred in different
places and in more or less temporary pools. The food conditions
in these breeding places would vary from .time to time and inde-
pendently of each other and that this might cause the variation
in the percentage of females found.
It has been pointed out.by Smith (1902) that the
male mosquitoes do not fly as faz as females and tlat more fe-
males enter the house. Smith caught a number of specimens outside
near the house, and a number inside, a total of about thirteen
hundred and fifty. Thore were several species represented and
for those taken outside, there -.'ere only a small percentage .
( 0 to 253) of males of the species that bred considerable dis-
tances away, while for Culex pipiens, which was breeding local-
ly, there were about sixty per cent of them males. Of the
total three Hundred and eighteen caught within the house, not
a single nale wias taken. Lefroy (1907) caught an average of
only 21.8% of females in traps situated within the house. I
have several ti:m.s counted the number of male an' females
restin- on t'-e -.alls of the Experiment Station toilet and h>ve
found that it .'.as very variable, but us! es were in the
abun e:e.-*. In one case, twe-'y-fc-.-ur rles .: e -ao feiales were
The n-'. r 1 -n he having bl6od in th'e abdomen, are
those in which the clotted bloo-d oo--ld actually be seen. Some
of those given as havin -J.ell developed ovaries v.ere those in
which the abdomen was distended. Some of those counted as hav-
ing the ovaries developed probably had the -bdomen di tended
with food. The. per centages of e-ch are based upon the number
of female e.u -ht. In the average of twrenty--five dissections
made, the number of well developed eggs varied from thirty to
one-hundr .d and thirty, depending very much on the size of the
female, with an average of 80.5. There seems to be no cor-
relation between the number with blood in t'e abdomen a-'d the
number with developed ovaries or the number cuglht.
Table VI.-The total number of each species identified, .and its
p: cent; -e of the total number identified for the
Species Total n mber Percent
Culex quinquefasciatus 20068 98.22
Anopheles crucians 101 .79
Anopheles quadri:-aculatus 197 .96
atesomyia calopus 3 .02
Psorophora ciliata 2 .01
This table gives some idea of the relctiv- numbers
of the differ nt species present, but it places Culex quin-
quefasciatus to hi'h. The n-mber of thc different species
present, varies con: ider:bly frorn tine to ti-ri and around the
-::)eriment Station anm dormitories, Cul:;x quinquefasciatus
usuall:.r makes up -eventy-five to eiiht p-r cent and perhaps
im re during January and February. At the Z:7ieriment Station,
during' December, scarcely any Culex -ere -een, while Anopheles
-ere pl _nt-'fi-l. mo4pheles usually constituted fifteen to
twent'- per cent of t"ose found in the dormitories during: Octo-
ber and "ov' .1. "o AnLop"'eles qua.rimacul'tus were seen rest-
ing on t'-3 w'.indow scre -ns at Shaw's until abou December 1st,
while Anopheles crucians usually formed five to ten per cent of
those found and sometimes more. After December 1st, until about
February 1st, both species were found, but u:.ually more inoph-
eles nuadrimaculatus. Then .. crucians became -ore abundant,
ma'kin_ up -about ten per cent of those present and occasionally
more. On March' 29th, I counted twenty-five A. cruci:.:ns arc
only two Culex pipiens. Stegomyia is sometimes foun' but never
very abundant; During October and Tovember, it was often found
about the Experiment Station, an: IT have caught them in Science
-Hall several ti-ies during the year.
Bsorophora and Megarhinus are only occasionally seen.
In one lot of :bout two hundred specimens taken in t'e Agri-
cultural 7uildi: Psorophora nade up about seenty-five per-
cent, knopheles fifteen per cent, and Culex, tegomyia, etc.,
about ten por cent. T'is was very unusual and was due to some
nearby, breedin- place. During LIay, Psorophora foroidense were
troublesom-.i in Science "'all at ni-ht.
a while tables IV. and V. give t'-e total number cou-ht
per month, it doe, not -ive the relative numb r of mosquitoes
present, f-,r toe fame number of t aps were not always ,et; the
position of the traps. 'as changed, etc. Table VI. "ives the
ave :-a- e number *aught per month in similar croc's at th> south
east (S E ; c) cnd of Derger's porch and at the ri-~h.t of the
door at Shaw's (D:r)
Table YI.-Avera e number caught r month in si-ilar crocks at
er:e.s 's and Show's.
Month Average Numbe '; caught Aver .e number
per night at 3erer's cau-ht per night at Shaw' s
Sept. 21 30.1
Oct. 44.2 78.7
L;ov. 1.3 23.2
Dec. 14.2 32.
Jan.-15 12. 13.
Feb. 14. 5 25.
TIarch 31.1 49.
April 12.2 30.
May 10.5 22.3
Average for the year 19.3 33.9
This table -ives the relative n--ber of mosquitoes pre-
sent during the different months and also shows the number
caught be a single trap. It is seen that there a.'e always
mort present at Shaw's than at Ber er's but that an increase
at one "lase is always shown at the other. This is to be ex-
pected, for while the noscuitoes found at the two places do not
have the sne breeding place, conditions favoring development
in one would likewise affect the other.
The number caup't At Ser war's from February to May,
did not eocrease as expected after University Place was drain-
ed. Some of the mosquitoes rau'ht here may have come from
Language Eall which continued to breed them in abundance.
Durin- :arch, Dr. c3r gee's cesspool was found teeming with
larvae and durin- April a tub in his b'clk yard was found to
be a breeding place. As the adults live for several weeks,
all of those th: t ha bred local.y7 had not died and the others
coming in front Lanjua._e `all kp'1 the supply up.
The Table .,hous the months when they were most abudi-&
ant, which, meas t t t they a: -e breedin- -'aster. It is ceen
that after Sept.b; and October in the F-ll, the' are not so
nu:u3rous, ,which cDrresponds with observations made on the breed-
in- areas. The spring; months have been unusually dry and very
unfavorable for breeding. It was pointed out' that those caugt
at S'haw's bred mostly in the pools and p'.ddles in the nearby
marshy) area northli of the house, and that these were formed b-
the rains. The .ry weath r this sprin- has prevented these
puddles front formin" and consequently the number -present at the
tw7o places does not show as much variation as the- would under
normal weath r conditions. -L-s. Shaw tells me that they have
been troubled lest, by t'hen this -prin- than at any tine during
the year since they have occupied the house. Then too, catch--
in', a loar '-r of ti.. early sprin irool in "'eb ary and
Marc' "n the traps probably has decrea -d the inm'ber enou"' to
account for sono- of t` difference.
Practical U e of T-ap.
Trap, of- this nature will no' rid a lace f fros-
auitoes, and in so.e. cases 7ill not reduce the number enough
to make the unobjectionable. But in favorable positions, they
will catch lar e Lu-be rs a-,- certainly could be used as a. con-
trollin `cetor. The 'v-r v numb er can u-'h1 th'ou-hout the year
( ieptenbeE to 7.:ay) by a sin -le crock at Sh:aw's -.nas thirty-
three. This .7oul" riive a total of twelve hundr: d for the year.
Suppose on. thousand houses in .'ainosville- s would run two of
th_ traps, ono on t-. front porch and. one on th; b c'- p:och for
year. This ... re. the ;ity of tjenty-four million pests-
I dare say more t.an have been killed by artificial meanc with-
in the city i- t' 1st ten y-a:s. Certainly tbey are not so
plentiful in "ai-e:vill -hat th -ce t.-e--ty-fou: trillion would
not be -" sed. 3 t eve- this is not all; for each female caught
during th winter and spring is ca abe of producing at least a
thous-nd others .during the suimrer. If. every home would co-
op rat ': runnin~- one or two of these tra-,s at last durin-
th.- .-int an -r:.y spring, the number of rnosuitoes present
would be greatly reduced.
1.- All of the mosquitoes found at the University bread
locally but the breeding areas are small and could be
drained with the expenditure of a small amount of money.
2.- Traps used for adults, when favorably located, have
caught an average of thirty-three mosquitoes per night
for nine months.
3.- Crooks or boxes lined with dark cloth have given
the best results. They should be small and deep.
4.- The success or failure of the trap depends on the
location. They should be placed in a well lighted room
or porch, which is free from dark cupboards, closets,
etc. The best position is determined by experiments.
5.- High winds affect the number caught, but temper-
ature is the most important factor. The largest numbers
caught were on warm still nights.
6.- All species are not equally attracted to the traps.
Culex quinquefasciatus is attracted more than Anopheles
7.- These traps are not recommended to rid a place of
mosquitoes, but if used with judgment they will reduce the
numbers found in the house.
Berkley, W. N. 1902 Laboratory Work With Mosquitoes.
Darling, Samuel T. 1910 Studies in Relation to Malaria. Pub-
lication of the Isthmian Canal Commission, Laboratory.
of the Board of Health, Department of Sanitation.
Davis, J. J. 1906, The Number of Eggs of Culex Pip4ens.
Entomological News, Vol. 17 No. 10, p. 368.
Felt, E. P., 1910, Report of the N. Y. State Entomologist
Francis, 1906 Public Health Notes Vol. No. 26, June 1909.
Gorgas, W. C. 1912, Report of the Department of Sanitation
of the Isthmian Canal Zone for 1912.
Gorgas, W. C. 1909, Larvaecides. Report of the Department
of Sanitation of the Isthmian Canal Zone for 1909.
Herrick, Glen. W. 1903. The Relation of Malaria to Agriculture
and Other Industries of the South. Popular Science
Monthly, April 1905.
Howard, L. 0. 1909. Mosquitoes, How they live: How they Carry
Disease: How they are Classified: How they may be
Howard, L. 0. 1911, Some Facts about Malaria. U. S. D. A.
Farmers Bul. 450.
Johnson, H. P. 1902. A study of Certain Mosquitoes in New Jer-
sey and a Statement of the "Mosquito-Malaria" theory.
Appendix A.,N. J. Agricultural Experiment Station.
Report of the Entomologist for 1902.
Lefroy, H. Maxwell 1907. A preliminary Account of the Biting
Flies of India, Agricultural Research Institute.
Pusa, India. Bul. 7.
Lugger, Otto 1896 Report of the Entomologist Maine Agricul-
tural Experiment Station, Report for 1896.
Mitchell, Evelyn Groesbeck, 1907. Mosquito Life.
Quale, H. J. 1906. Mosquito Control. Cal. Agricultural Ex-
periment Station Bul. 178.
Smith, John B. 1901-1911 Report of the Entomologist for 1901-
1911. New Jersey Agricultural Experiment Station.
Smith, John B, 1908. The House Mosquito, A City, Town, and
Village Problem. New Jersey Agricultural Experiment
Station Bul. 246.
Theobald, F. V. 1901. Monograph of the Culicidiae or Mosquitoes
Official Publication of the British Museum, London.
Van Dine, D. L. 1906. Mosquito Control. The Introduction of
Top Minnows in the Hawaian Islands. Hawaian Station
Press Bul. 20.
Explanation of Fi:ures
Fig. 1. 2g -*ft of Julex quinquefasciatus.
Fig. 2. Larvae of 0. quinquefacits owir' the long anal
tube and t'-e oblique anIle at which they hang from
2ig. 35. Anal or respiratorT- tube of Culex quinquefasciatus.
Fig. 4. L:eaGL. y Julex ,uiinquefasciatus (Enlarged.)
Fi 5. Larvae of Oulex q-inquefasciatus (InEarged.)
Fi-. . -Cult of JOlex quinquefasciatus (Aft-r lov,-ard.)
Fig. 7. Position of Culex quinquefasciatus on a vertical
Fig. 8. "oad. of lale Oulex quinquefasciatus, showing plumose
antennae and long palpi.
Fig. 9. lead of fen:ale Gulex quinquefasciatus sho- ing pilose
antennae anC. short palpi.
Fig. 10. Wing of 6ulex quinquefasciatus.
Fig. 11. Eggs of Anopheles (After Nuttall anC Shipley)
Fis. 12. Larvae of Anopheles resting at the surface.
Fig. 13. Larvae of Anopheles seen from above.
Fis. 14. Posture of Anopheles on vuall. (After 3,;rkley)
Fig. 15. Position of Anopheles on wall. (After Doane)
Fi 16. "`sad of "ale Anopheles (Enlarged).
Fig. 17. Head of female Anopheles (Enlarged).
Fig. 18. ,ing of Anopheles (Enlarged) crucians.
Fig. 19. Jing of LAnpheles nuadrimiaculatus (Enlarged)
21. 20. Pup,.e of stegomyia calopus.
Fig. 21. Adult o? Stegoiayia calopus (!nla ged) After Goeldi)
Small figure- shows natural size and position on ,-all.
Fig. 22. Top Miinnow (Gambusia affinis)
Fig. 23. Gogjle-eye or wvarmouth perch (Chaenobryttus rulosus.)
Fig. 24. La-in3 sewer pipe in University Place.
*i 25. View in University place with the vegetation anc w-.ter
Fig. 26. Vieu in University Place showing the improvement
Fig. 27. Crock that Z ve good results as a trap.
Fig. 28. Crock that Sav-, poor results as ac trap. T.ote the
large diameter anCl- nall depth.
Fis. 29. TQe different sizes and shapes of boxes and crocks,
etc., used for traps.
Fi. 30. A convenient cover for t_.-ps made of a frame covered
with wire ';auze.
Fi". 31. Dia-ra: porchews at merger's and Shaw's showing the
various locations referred to.
Fig. 32. Curve showing the correlation between the temperature
and the number of mosquitoes caught per ni:ht. The
Figures at the left indicate the temperature, those
at th:; bottom the date, and those at the right,- t e
n'-mber of mosquitoes caught.
Fi.. 33. Curve showing the percentage of the total number
caught which were females, the percentage of the fe-
males with blood in thi abdomen, and the percentage
of females *;ith ,.ell developed avaries caught per
month at Berger's and 6haw's.