Title Page
 Table of Contents
 Part I
 Part II

Title: Mosquito conditions at the University of Florida
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00096260/00001
 Material Information
Title: Mosquito conditions at the University of Florida with an account of experiments conducted with traps for adult mosquitoes
Physical Description: 34, 28 leaves. : ill. ; 28 cm.
Language: English
Creator: Loftin, U. C. ( Ulphian Carr )
Publication Date: 1910
Subject: Mosquitoes -- Florida -- Gainesville   ( lcsh )
Genre: bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )
Thesis: Thesis (M.S.)--University of Florida, 1913.
Bibliography: Includes bibliographical references (leaves 27-28).
General Note: Typescript.
Statement of Responsibility: by U. Carr Loftin.
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Bibliographic ID: UF00096260
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 13919637

Table of Contents
    Title Page
        Title Page 1
        Title Page 2
    Table of Contents
        Table of Contents
    Part I
        Page A-1
        Page A-2
        Page A-3
        Page A-4
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        Page A-34
    Part II
        Page B-1
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Full Text


at the


WVith an account of exneriTments conducted with

tro s for adult mosquitoes



?. S. '. C. A. & College

....................... !-"i-' '
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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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*. *...
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S. .
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*.* .*. *.
*..*.*..** *
* *.~ *
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.** .*** *
* ** .**
S. .


Part 1.


Local Con--itions

Soecies found with descriptions and
breeding places

Yosouitoes and Disease

Natural Enemies

Prev ntives and Remedies

Remedies against Larvae

Draina ,e

"Low the work at the University can be done

Part II


Description of trap

Killing agents

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

species caught

Relative abundance duarinj t:' year

Practical use of traps


Page 1
" 2
























Part. I.

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,

Abner would 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.

Local .,Conditions.

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-

iment Station.

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.

Species Found.

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

Megarhinus sp?

Following is a brief description of these speci-s.

Culex quinquefasciatus.

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.

Breeding Places.

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.

Breedin. Places.

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

Culex Larvae.


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.

Breeding Places.

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


found here,..

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.

Yellow FeVer.

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

Panama Canal.

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

to drain.

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-

ing places.

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

at present.

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'-

quito proof.

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.

Part II
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-

quitoos trapped.

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

than bottles.

"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
per night.

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

the traps.

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

the screens.

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

was windy.

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-
tract nos',uitoes

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.

Culex quinquefosciatus

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

Anopheles Cruoians
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

Anopheles quadrimaoulatus
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

Culex quinquefasciatus
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

Anopheles Crucians
-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

Anopheles Quinquemaculatus

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

20431 100.00

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

or Stegomyia.

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.

Literature Cited.

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

for 1905.

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

th) surface.

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

before draining.

Fig. 26. Vieu in University Place showing the improvement

since drainage.

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.

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