The Great Mosquito Safari: A Collecting
Trip with William Horsfall
|William Robert Horsfall, 1908-1998
by Robert J. Novak, Jimmy K. Olson, & Daniel Strickman
Dr. William R. Horsfall, professor emeritus of the Department of
Entomology, University of Illinois, passed away at the age of 90 at his home at the
Clark-Lindsey Village, Urbana, IL, on November 18, 1998. He is survived by his wife of 68
years, Annie Laurie Ellis Horsfall, and was preceded in death by a sister and two
Dr. Horsfall was born on January 11, 1908, in Mountain
Grove, MO, but spent most of his formative years in southwestern Arkansas where his father
served as President of what is now the University of Arkansas at Monticello and his mother
served as that institutions first Dean of Women. After receiving his B.S. degree in
biology from the University of Arkansas in 1928, and his M.S. degree in agriculture from
Kansas State University in 1929, Dr. Horsfall entered into study under Professor G.W.
Herrick at Cornell University and earned his doctorate degree in entomology in 1933. He
taught at Cornell for a time and then, up until World War II, he held faculty positions at
the University of Arkansas-Fayetteville and South Dakota State University-Brookings, where
he was also Head of the Department of Biology.
During World War II, Dr. Horsfall served in the Pacific
Theatre as Commander of the U.S. Armys 17th Malarial Unit. After 3 years of service,
he was discharged as a lieutenant colonel and rejoined the entomology faculty at the
University of Arkansas-Fayetteville. Dr. Horsfall remained active in the U.S. Army
Reserves after his discharge and retired from this activity in 1965. In 1947 he joined the
Department of Entomology at the University of Illinois-Urbana-Champaign as an assistant
professor in medical entomology, a position he held until his retirement as professor in
Most mosquito people will remember Dr. Horsfall as the
scholarly master of the bionomics and management of mosquitoes, particularly floodwater
varieties. He actually began to develop his basic philosophies about insects and their
control while he was working on such insects as grapevine sawfly, Erythraspides
pygmaeus (Say) as a student at Cornell University. His conception of insect bionomics
was strengthened and fine-tuned while working on meloid parasitoids of grasshoppers at
South Dakota State University. Dr. Horsfalls favorite quote to his students stemming
from that era of his career was, "Effective control measures are dictated by the
bionomics of the insects." Unfortunately this critical concept was lost to us during
the chemical age of 1945-1965, but was considered a novel approach with the
advent of the integrated pest management paradigm of the 1970s.
Many having known Dr. Horsfall personally as well as
professionally point to his military experience as the time when he began to see the
potential for applying his basic philosophy to manage mosquitoes and mosquito-borne
diseases. Armed with the bionomic information he had gathered on the mosquitoes of New
Guinea, and with oil as his only larvicide, he led his malaria survey unit to accomplish
the near elimination of malaria as a problem on that island.
Dr. Horsfalls scholarly potential became fully
kinetic when he joined the entomology faculty at Illinois. In this atmosphere, he
developed and taught a variety of courses focusing on insect bionomics, insect control,
and medical entomology. His research efforts were centered on mosquitoes, mosquito-borne
diseases, and their control. In the process, Dr. Horsfall also mentored some 21 doctoral
and 20 M.S. degree students in medical entomology. Over his career, Dr. Horsfall published
five books and more than 140 scientific papers and bulletins. An active member in the
American Mosquito Control Association, the Entomological Society of America and many other
professional organizations, he served as a consultant to governmental and academic
agencies worldwide, including the World Health Organization, National Science Foundation,
Department of Defense, U.S. Public Health Service, U.S. Environmental Protection Agency,
U.S. Department of Agriculture, and the Tennessee Valley Authority. Dr. Horsfall was a
founder of organized mosquito control in Illinois and was an organizer, charter, and first
honorary member of the Illinois Mosquito & Vector Control Association.
Dr. Horsfall received many honors for his scholarly
achievements and contributions to entomology and science in general. He was the first
recipient (along with Maurice Provost) of the AMCAs Harold Gray Memorial Medal of
Honor and received such other prestigious awards as AMCAs Distinguished Service
Award, the American Society of Tropical Medicine and Hygienes Harry Hoogstraal
medal, the Finnish Zoological Societys Award of Merit, and the University of
Illinois Wakefield Award for Excellence in Teaching. Also, in expressing his loyalty
to the affairs of the University of Illinois, the institution honored him with membership
into the Presidents Council, and the Centuria Circle, its highest donor recognition
award. Dr. Horsfall and his wife, Annie Laurie, were also recognized by the University for
their generous support to the University Library and the Spurlock Museum of World Culture.
Despite all the awards and recognition Dr. Horsfall
received for his scholarly achievements, he found his greatest satisfaction and reward in
his students. He took great pride in his entomological pedigree, which began with
Professors Comstock and Herrick and extended on through him to the students he mentored.
As a mentor, Dr. Horsfall was a demanding taskmaster and the stories lovingly abound among
his former students as to who had it the toughest. However, his gruff nature was only a
veneer; for, underneath the rough exterior, there was a true humanitarian who cherished
his association with students. He understood that, for a student to become a competent
professional entomologist, he or she had to be tempered with hard work and discipline in
and out of the classroom. The Horsfall pedigree, known as the "Horsfall Mafia,"
now extends to the third and fourth generations.
Dr. Horsfall students will agree that, while he was
cap-able of such detailed and erudite work as embryonic development of mosquitoes under
thermal stress, at the same time, he kept a strong connection to the practical roots of
entomology. Considering his clear communication skills, acute scientific instinct, total
honesty, curiosity, and warm humility, Dr. Horsfall was the ideal model of an entomologist
for his students. He will be sorely missed but his legend and legacy will continue to live
on in his students and their memories of him as teacher, mentor, counselor, and friend.
"Rework" no more! The "Doc" has laid down his red pen. [back
The Great Mosquito Safari: A Collecting Trip with William Horsfall
by George W. Swenson, Jr., Professor Emeritus, Department
of Electrical Engineering
Reprinted with permission from the author
The faithful Seven-One-Papa was fueled and ready on the
ramp of Illini Airport. The special trailing-wire antenna for the high-frequency radio was
rigged and ready to be reeled out when needed. The twin 160-horsepower engines had had
their 100-hour inspections and were certified in A-1 condition. The sextant and almanacs
were aboard and our wristwatches had been carefully calibrated. We were only two on this
tripno use carrying extra weight, so the two rear seats had been removed. In their
place was strapped a strange collection of equipment, representing the fieldwork
necessities of an entomologist and a radio engineer, respectively. Of course, the load
included sleeping bags, fishnet, axe, cooking kit, tent, rations, and other emergency gear
required by Canadian regulations for wilderness flights.
Bills wife came to see us off. Annie Horsfall had
witnessed the departures of many expeditions, apparently. She murmured to me,
"Dont let Bill feed more than 5000 mosquitoes per day. It makes him sick."
I looked at her in disbelief, but she seemed perfectly serious. Still, I thought she must
be pulling my leg. Little did I then know!
Bills mission was two-fold. He had a notion that
mosquitoes breeding in an environment of relatively high radioactivity might have evolved
some mutant forms. Wed collect some specimens on the tailing dumps of the old radium
mines on Great Bear Lake, far up in the Northwest Territories. He also wanted specimens
from the barren arctic tundra to study what developmental adaptations the insects make in
response to extremely severe environmental conditions.
My job was to overhaul the radio equipment, install new
antennas, train the new operator, and generally show the flag at our satellite tracking
station at Baker Lake, Northwest Territories. Baker Lake is an Eskimo village in the
barren lands, hundreds of miles north of the tree line. It should be an excellent place
for the kind of studies Bill had in mind. A year and a half earlier Id visited there
in winter, and could certify to the extreme cold and violent winds the over-wintering
mosquito eggs would have to survive.
Our route took us directly from Urbana, Illinois, to
Winnipeg, Manitoba, an uneventful flight in good weather, with a stop at Bemidji,
Minnesota, for fuel. Seven-One-Papa, the Piper Apache, purred along contentedly while I
explained to Bill the operation of the VHF Omnirange, the automatic direction finder, the
directional gyroscope (DG), and other navigational aids. I even practiced calculating the
azimuth of the sun and setting the DG without reference to the magnetic compass, a trick
wed have to use when flying within a few hundred miles of the magnetic pole.
At Winnipeg we cleared Canadian customs, refueled, and
found a hotel for the night. Next day we proceeded north-west between Lakes Winnipeg and
Manitoba 640 km (400 mi.) to Flin Flon, on the Saskatchewan border. Flin Flon is a mining
town on the rocky Laurentian Shield among a myriad of lakes. There was an excellent
airport, 5 miles from town by air but 20 miles by the road that meandered among the lakes.
There was a taxi in town, but no telephone at the airport with which to summon it. There
was a phone in a booth by the runway with which one could request a weather forecast.
Unfortunately, these forecasts were only good for a 4-hour period, and were usually 6
hours late, by which time we already knew what the weather had been. This weather service
was not available in town either, but only from that particular phone. Clearly
communications were going to be a problem as long as we were in Flin Flon.
A fisherman with a pickup truck solved our immediate
problem by taking us to the hotel in town, where we had a good supper in the Chinese
restaurant, one of Western Canadas ubiquitous institutions. A good nights
sleep was next on the agenda to prepare us for a long days northward flying, first
to Yellowknife, then to Great Bear Lake.
The weather was not encouraging on June 22, but we took
advantage of a little break in the clouds to fly toward Yellowknife, hoping the clouds
might lift toward the north. But our bad luck stayed with us; 75 miles out we were turned
back by thick clouds reaching right to the ground. We followed our ADF back to the Flin
Flon broadcast transmitter, then landed for refueling and another night in town.
We awakened on June 23 to rainy, gray skies and im-possibly
poor visibility. We taxied to the airport anyway, to suffer hours of frustration trying to
get timely weather forecasts. Back to town for another night. Time, at least, for
exploring this interesting town, built on a rock so solid the utilities normally buried
below frost line are here on the surface, enclosed in boxlike wooden ducts insulated
against the cold.
By great good fortune on June 24 we were able to get timely
weather predictions for a flight to Churchill, Manitoba, 640 km (400 mi) to the northeast
on Hudson Bay. If we left immediately we could make the trip under visual flight rules and
be there before dark. We couldnt spend all summer trying to get to Great Bear, could
The flight was across a true, trackless wilderness, away
from all established air routes and radio aids. The sensation of solitude has always
thrilled me, and here we had 3 hours with never a road, a village, a wisp of smoke in
sight. Thirty, even 20 years ago one could easily find such places in Canada and Alaska.
Now, sadly, they have become all too rare, as the network of roads, airports, and radio
beacons spreads inexorably into the remotest parts of North America. This was my first
visit as pilot-in-command, and I was fascinated by the hangar talk of the local bush
pilots and airline personnel: unpublished but useful radio frequencies, a rumored cache of
aviation fuel at such-and-such a lake, a new emergency landing strip at so-and-so mining
camp, and other valuable gossip. The station manager of Transair, Ltd., the regional
airline, took us home for dinner and befriended us in many ways. He later undertook to
collect mosquitoes for Bill over a period of years.
Bill wanted mosquito specimens from several locations:
live, biting, pregnant females that can be counted on to deliver eggs when they arrive
back in the Illinois lab. Churchill was our first good chance, so I got a lesson in
collection technique. The basic equipment consisted of a plastic tube, about a centimeter
in diameter and ten centimeters long with a nylon screen cemented over one end. A small
cage is provided, the size and shape of a snuff can, with top and bottom of cork and
cylindrical side of window screen. Bill demonstrated the capture technique. Sit on a rock
with sleeves and pants legs rolled up. Only pregnant female mosquitoes bite, so one is
assured of catching the right ones. When an insect lands on bare skin, the open end of the
tube is placed over her, whereupon she flies upward into the tube. The tube is rapidly
moved to another one, and another. When a dozen or so are accumulated, the open end of the
tube is inserted into a hole in the top of the cage and the collector blows gently into
the screened end to move the mosquitoes inside. The cage is stoppered, and the whole
process is repeated until the cage has about 200 specimens inside.
Bill is very adept at this, and indifferent to the obvious
hazards. In fact, he seems to have substantial immunity to the insects toxins,
acquired by years of exposure. I, on the other hand, have a well-ingrained distaste of
mosquito bites. I evolved my own collecting technique, involving only one bare arm at a
time. Naturally, my collecting rate was much less than the norm, but after all, I
wasnt getting paid for this.
Bill wanted the mosquitoes to deliver eggs as soon as they
arrived at Illinois. To do that they must have a blood meal before the return flight.
Bills method was to place a screened cage against his bare chest, whereupon he would
instantly be bitten by 200 ravenous, single-minded insects. To achieve the maximum
possible production, he hinted rather strongly that other volunteers would be welcome, but
I decided that my obligation to science would extend only to service as pilot, navigator,
general expediter, and cheerleader. We collected several crates of mosquitoes in cages,
which were stored in a hangar at Churchill to be picked up on our return trip.
The flight to Baker Lake was also uneventful, but very
interesting. Churchill is at the northern limit of trees; beyond is only tundra. Still,
the land is beautiful in an austere fashion, dotted with blue lakes amid the gray-green
grasses and sedges, with visibility that is spectacular in the clear, arctic air. A smooth
landing, followed by a trip to the village in a dump truck, and we settle into our
quarters in the government laboratory. Baker Lake, is connected with Hudson Bay by
Chesterfield Inlet, a 200-mile-long freshwater channel. Supplies came in by barge in the
summer, so its a natural place for a government weather station, magnetic
observatory, and regional administrative headquarters. A corner of the magneticians
laboratory is available for our satellite-monitoring equipment, gathering data for studies
of the ionosphere.
One thing puzzled us when we opened the door of the plane
after landing at Baker. Where were the hordes of mosquitoes wed learned to expect?
Wed telegraphed ahead before leaving Illinois and had been told the snow was mostly
gone and the tundra was dotted with meltwater pools. There should be mosquitoes, but there
werent. This was a serious setback, especially after our disappointment at not
reaching Great Bear Lake. A quick investigation of the pools showed them to be alive with
mosquito larvae, prompting me to ask why we shouldnt bring back larvae instead of
adults. Because we havent the means, and because its not an efficient way to
get eggs, Bill explained, as half the larvae are males. Still, it would be worth a try, as
an alternative to complete failure.
The Hudson Bay Company store, surprisingly, had dozens of
picnic-sized thermos bottles in stock. We bought them all, as well as a white-enameled
dipper. We quickly gathered a large number of larvae and incarcerated them in the bottles,
in meltwater exactly the same temperature as that in the pools. Theyd have to be
maintained at that temperature until they metamorphosed into adults in Urbana. We froze
ice cubes of non-chlorinated meltwater in the kitchen freezer, and tended the larvae
Of course, they had to be fed, too, but fed what? Bill
didnt know what these particular larvae ate, so he set out to learn. After a couple
of hours belly-down beside several pools, he announced his finding: "Lemming
droppings!" Lemmings, those legendary Arctic groundsquirrels, were everywhere on the
tundra, so it shouldnt be too much trouble laying in a suitable supply of rations
for our larvae. All this activity required Bill to roam fairly widely about the tundra
while I remained in the village tending to my electronic affairs. The tundra is rolling,
if not actually hilly, but essentially devoid of landmarks. It would be easy for a novice
to get lost, so it seemed a good idea for Bill to have a guide. The village fathers
assigned the task to a teenaged Eskimo boy, who proved an invaluable assistant and an
unerring pathfinder. The two of them spent hours on hands and knees before pools and
lemming burrows, and Id have paid a lot for a translation of the commentary in the
Eskimo community regarding the habits and interests of visiting white men.
After 3 days Bill and I had completed our respective
chores. The larvae were apparently thriving in their thermos bottles on their remarkable
diet. It was time to head for home. The weather at Baker Lake looked fine and clear and
the radio report from Churchill was good. We filed a flight plan for Churchill under
visual flight rules and set out bright and early. We climbed to 9000 feet and headed south
across the lake, then made a bee-line across the tundra. More bad luck! About 50 miles out
we ran into impenetrable weather, a snowstorm, and had to turn back.
Another night at Baker Lake, and more waiting for weather
reports from Churchill, relayed by Morse code via Coral Harbour, hundreds of miles to the
north on Southampton Island. Next day we set off again, this time reaching Churchill
easily, and there picking up our adult mosquitoes and pro-ceeding southward again.
Armstrong, Ontario, is our next stop, at the northern end
of Lake Nipigon. Its a long flight from Churchill, the long-est of the entire
expedition, stretching our fuel capacity to an uncomfortable degree. Good weather allows
us to enjoy one of the most beautiful, wild stretches of forest country in North America.
Careful navigation is important here, too as were flying well off the regular air
A small timber-industry town, Armstrong is on the
trans-continental rail and air routes, but is hardly a sophisticated tourist center. We
found a room in a tiny, primitive hotel over the town bar. The night began with an
hours-long riot in the barroom downstairs, as lumberjacks and cat-skinners worked off the
weeks tension, and ended in the wee small hours with a violent battle between the
hotel manager and his wife in the room next door. Screaming and yelling, punctuated by the
thudding of fists, kept us awake all night. Should we intervene, or try to locate the
police? There is no telephone. Were far from our own turf, uncertain whether this is
a routine occurrence or a real emergency. Daybreak ended our indecision and we hastened to
the airport for a short trip to Thunder Bay and outgoing customs inspection.
Next, we filed a radio message to U.S. Air Traffic Control,
requesting incoming customs and immigration inspection, and took off across the middle of
Lake Superior. The Big Lake is always beautiful and somehow mysterious. The route leads
directly across Isle Royale National Park, from the air a lake-spangled green tapestry
laid upon the blue sea, partially shrouded in mist. A few lake freighters move below us,
carrying grain and iron ore from Duluth to Sault Ste. Marie. Then we cross the tip of the
Keweenaw Peninsula and maneuver for a landing at Houghton County Airport.
The customs inspectors face registers surprise when
we announce our cargo, and he examines meticulously Bills U.S. Department of
Agriculture permit for importation of live mosquitoes. A car pulls up to the ramp and my
father and mother emerge, summoned by telephone from Thunder Bay. We motor to their home
in nearby Houghton, to spend the night and to collect still more mosquitoes along the
shores of Portage Lake, my boyhood playground.
Mothers refrigerator provided ice cubes, of water
first boiled to eliminate chlorine. We clustered around the kitchen table, tending our
insect charges, feeding them and cooling their water to the proper temperature for the
last leg of the trip back to Urbana. The episode made an indelible impression on Dad and
Mother, providing stories for Rotary Club and Church Circle luncheons in subsequent years.
They capitalized on it many times.
As have I. [back to top]