METHODS DIRECTED AGAINST ADULT MOSQUITOES 
303 
of 25,200 yards to the pound. Copper wire 
screening in the 16/16 mesh, 28 S.W.G., 
recommended by LePrince and Orenstein 
(1916) for the Canal Zone, was found to 
possess the maximum safe aperture for use 
in Africa by Davey and Gordon (1938). 
Mulligan and Majid (1932) stated that 
apertures somewhat larger were satisfac¬ 
tory for India. Earle (1932) judged that 
12-mesh copper of 0.015 inch diameter wire 
was probably the best screening material 
for Puerto Rico. 
Traps 
Traps providing an attractive resting 
place for adult mosquitoes have been exten¬ 
sively used in India. Those reviewed by 
Covell (1931a) have been supplemented by 
the feather duster and earthen pot traps 
described by Gore (1937a, 1937b). Russell 
and Santiago (1934) devised a box-like trap 
for anopheles which had a layer of soil one 
inch thick held in place on the inside walls 
and roof by 16-mesh screening. A drip- 
can on the roof kept the soil moist. The 
trap bottom was open and the one end not 
boarded up was partially closed at night by 
a black cloth which hung to within 6 inches 
of the ground. The box was placed di¬ 
rectly on the ground and collections were 
made with glass vials in the morning. The 
smallest effective trap of this type used in 
the Philippines was 2 feet wide, 2 feet high 
and 3 feet long. 
In the Orient human-baited traps have 
been effectively used. Manalang (1931) 
captured females of A. funestus Giles 
(minimus) in a wire screen cage baited 
with a man sleeping under a mosquito net. 
The collector did not risk contracting ma¬ 
laria and mosquito collection was made 
relatively easy. Urbino (1936, 1938) and 
Ejercito (1938) also reported the use of 
man-baited traps to determine the density 
of A. minimus var. flavirostris. Gater 
(1933) found that a double bed net, of 
which the outer had openings that were 
closed with flaps at intervals during the 
night, was many times more effective than 
hand catches in the collection of Malayan 
anopheles. 
In Panama a V-shaped ridge of screen¬ 
ing with a slit cut in at the apex enclosed 
in a screen wire housing was used with suc¬ 
cess by Bath (1931) to entrap mosquitoes 
attracted to human scent. The unit was 
mounted at the top of a window or in the 
wall of a building. Mosquitoes entering 
the slit were confined between the ridge and 
housing screens. In the West Indies, South 
and Central America, animal baited traps 
have reached their highest state of devel¬ 
opment. Magoon (1935) illustrated a 
stable trap for the capture of anopheles 
mosquitoes in Jamaica. Earle and Howard 
described the portable stable trap em¬ 
ployed in Puerto Rico and stressed the value 
of studies of mosquito densities in the di¬ 
rection of control work. Earle (1934, 1937) 
used animal baited traps for a number of 
years to determine the feeding preferences 
of anopheles and to trace the reduction in 
density of A. albimanus Wied. resulting 
from mosquito control measures. Carr, 
Melendez and Ros, by means of calf-baited 
traps, found A. albimanus most abundant 
in the areas of greatest malarial incidence 
in the Province of Havana. Pereira Bar¬ 
reto captured A. darlingi var. paulistensis 
and other Brazilian anopheles attracted to 
a horse, and Gabaldon illustrated the burro- 
baited stable trap used in Venezuela. 
In a comparison of animal-baited and 
mechanical mosquito traps in Panama, 
Curry stated that the mechanical suction 
fan light trap was notably inefficient in 
obtaining information as to density of 
flights. A portable muslin and netting 
cage which could be suspended over an 
animal by cords was devised by Shannon 
(1939), principally for the capture of non- 
anopheline mosquitoes. In the capture of 
A. maculipennis emerging from hiberna¬ 
tion quarters in Central Russia, Khelevin 
(1938) employed glass plates covered with 
a mixture of one part castor oil and two 
parts colophony. 
In the eastern United States electric 
light traps have been widely used for sam¬ 
pling mosquito populations. The evolution 
of the New Jersey light trap from an illu¬ 
minated sugar can to electric fan suction 
