1915} Behavior of Anopheles 200 
Mosquito bar nets were stretched out at the breeding place, 
three sides of which were in close contact with the ground while 
the remaining side was raised about a foot or so from the 
ground. At about 5:00 p. m. a negro was placed inside of each 
net, with instructions to prevent as far as possible mosquitos 
biting him. Within an hour Mr. Negro shared his net with a 
thousand or more noisy mosquitos. More mosquitos entered 
nets when these were kept dark. | 
The noise made by these dens of voracious, unrestful 
culicids, their persistent, unceasing attacks, and the endurance 
of the willing and patient negroes, are things that can never 
be forgotten by those who had witnessed them. 
After having the nets full of mosquitos, the next step was 
to spray them. The usual vaseline nebulizer was used, and a 
1 : 100 solution of anilin dye in water sufficed to give enough 
color to the mosquito so as to be easily recognized if found 
later on. Spraying was facilitated by illumination from the 
outside. Two net-fulls of mosquitos were killed after sprayed 
and when tested showed a percentage of 98 positive. Within 
fifteen minutes after spraying the nets were inverted and the 
mosquitos allowed all the freedom they cared for. It was 
assumed that at, the end of this period a sufficient number 
would be in condition to take part in the flight to Gatun. 
At the same time similar nets were placed opposite the breed- 
ing place and elsewhere, with men, dog or hens as bait, and the 
mosquitos thus caught were examined for color. The results are 
given elsewhere. It is well to state here that due to the fan-like 
spreading of mosquitos from the breeding place, and the 
unusually well-screened and protected homes in Gatun, one 
cannot expect a large number of colored mosquitos in the 
houses. The proportion of colored mosquitos to non-stained 
ones is probably as high as one to three hundred. 
The following table gives the time, numbers, etc. of the 
marked mosquitos liberated. The direction, velocity and 
trend of the wind at the time of liberation is also indicated. 
Attention is called to the fact that the winds at such hours 
were generally of high velocity—a fact which should not be 
forgotten when one reads so many accounts that mosquitos 
do not fly when the winds exceed four miles per hour. Such 
speculative deductions are the natural results of looking upon 
