298 
MALARIA 
the day, in or under a house, a latrine, a 
shed, stable, in a culvert under a bridge, a 
tree hole, or any locality affording shade 
and humidity. They may or may not be 
related to a source of a blood meal. All 
collections from each location should be 
kept as separate units for identification. 
As minimal equipment in the search for 
adults there are required: a flashlight; col¬ 
lection tubes, either suction or chloroform; 
labelled pill boxes for individual collec¬ 
tions; and record cards, including labeled 
spaces for recording places of capture, date 
and hour; type of station, diurnal or noc¬ 
turnal catch; weather conditions during 
previous night; time spent in capture; spe¬ 
cies identified and numbers of males and 
females. 
As control work progresses, routine ento¬ 
mological investigations afford a check on 
the work, and routine visits at weekly or 
ten-day intervals should be made to areas 
selected after preliminary investigations 
have shown that the sites are frequented 
by adults. They should be chosen with 
definite relation to known breeding areas 
so that they cover the total area to be 
studied in a comprehensive manner. 
If it be necessary to demonstrate the im¬ 
portance of certain breeding areas, par¬ 
ticularly if located at about the maximum 
flight range of a species, the recovery of 
stained adults in nature as well as in spe¬ 
cial catching stations may be attempted. 
Some expression of the density of the 
anophelines should be adopted. When 
density is not great, comparison may be 
made between total catches, but when more 
abundant, results may be expressed as the 
number caught per man-hour (Boyd 
1930a). 
Analysis of the entomological data 
should yield the following information: 
density and distribution of local fauna, 
actual and potential breeding areas, rela¬ 
tion of production areas to clinical cases, 
flight range and direction of ingress or 
infiltration, and seasonal variations. The 
data should be entered on entomological 
spot maps. 
It is not expected that each survey would 
require a specific appraisal of the actual 
or potential role of the local anophelines 
as vectors. Information already available 
will generally indicate the vectors, since 
the results of intensive studies performed 
in a few typical and sample localities will 
likely afford significant information appli¬ 
cable to wide areas. 
If required, pertinent information bear¬ 
ing upon this question may be received 
from the results of precipitin tests per¬ 
formed on the blood removed from a series 
of stomachs of freshly blooded anophelines 
to ascertain the host from which the blood 
meal was taken. If the presumptive evi¬ 
dence suggests a species to be anthropo- 
philic, its susceptibility to infection with 
malarial parasites should be determined, 
and demonstration of the infection of this 
species under natural conditions may be 
attempted. The technique of the precipi¬ 
tin test is described by Rice and Barber 
(1935). 
If the terrain is unfamiliar and maps are 
not available, these deficiencies must be 
supplied by the engineer. Maps for the 
spotting of clinical and entomological data 
must be available immediately. Hulse’s 
(1922) sketch mapping for public health 
work is a very good introduction to the 
practical preparation of work maps. At¬ 
tention must be given to all residences and 
their distinguishing identifications and to 
water courses and collections, of water and 
depressions which may hold water tempo¬ 
rarily. Information relating to the geo¬ 
logical formation of the region and types 
of soil, as well as the past and current 
records of precipitation, may also be 
required. 
Furthermore, for convenience in the 
analysis of the data, the area covered by 
the maps may be subdivided according to 
civil or arbitrary subdivisions in order to 
accentuate local differences in data. 
Analysis of the Data Secured in the 
Survey 
The different portions of the surveys are 
complementary to each other, and in an 
appraisal of the situation their results 
