ind 
THE MOSQUITOES OF THE SOUTHEASTERN STATES 15 
breeding areas, and is indispensable in measuring the results 
accomplished. 
General methods of collecting mosquitoes have been discussed in 
a preceding section. Some of the special methods employed for 
obtaining data necessary in connection with surveys and control 
operations are described in the following paragraphs. 
BITING RECORDS 
Collecting mosquitoes while they are biting is the simplest and 
most direct method of determining the proportions of the different 
bloodsucking species. Such collections are usually made with a 
chloroform tube or other type of killing bottle. For data on com- 
parative abundance in different parts of the area or at different times 
of the year, stations are selected and collections made for equal 
periods and under conditions as nearly uniform as possible. In ob- 
taining such records the writers have adopted the procedure of sitting 
on a box or stool at the selected place, with the trouser legs rolled to 
the knees. After a minute or so has been allowed for the mosquitoes - 
to accumulate, they are collected as they alight, for a period of 10 
or 15 minutes (70/). If the collecting is done after dark, a flash- 
light is necessary. Two 15-minute collecting periods or three 10- 
minute periods may be totaled and multiplied by 2 for the hourly 
rate. Collections made during the first flight period (just at dark) 
should not be averaged with later collections, as the numbers are 
usually much larger at that time. 
When the mosquitoes are numerous, the numbers caught can be 
increased considerably by placing a short paper funnel, or guard, in 
the mouth of the collecting tube (fig. 5), since this permits the 
collector to move to the next specimen without waiting for the first 
one to succumb to the chloroform fumes. The guards are useful 
otherwise in conserving the strength of the chloroform and in pre- 
venting the loss of specimens when the mouth of the tube is turned 
downward. 
When collecting after dark the writers have taken an average of 
10 mosquitoes per minute, or 600 per hour, with a tube of this sort. 
If the mosquitoes are much more numerous than this, the discom- 
fort of collecting is so great that it is considered sufficient to record 
abundance as 600+, or other observed rate, per hour. When the 
collecting is to be done at different places by two or more persons, 
preliminary collections should be made at one place to determine the 
relative attractiveness and dexterity of the different collectors, as 
much variation has been found in these respects. — 
HAND COLLECTIONS OR COUNTS OF RESTING MOSQUITOES 
Some species can be obtained by daytime collecting in dark corners 
and other places where the adults (including the males) spend the 
daylight hours. This is an excellent method of obtaining compara- 
tive data on densities of adult Anopheles, especially those species 
found in the United States, since they fly into a shelter at daybreak 
and remain quietly there throughout the day. For these species also 
this method is much safer than the biting method, which is attended 
with danger of malaria transmission, 
