MOSQUITO CONTROL TESTS — STAGE 355 



Delayed by weather and by regulations, the flight took 4i/^ days. 

 Because we were flying by contact and had to remain low enough to 

 sight landmarks, we bumped along slowly, in steadily rising tempera- 

 tures. On the other side of the fuselage from our bucket seats were 

 eight 100-gallon fabricoid tanks stacked in front of windows. Part 

 of the floor of the plane had been removed to make room for the 

 discharge pipes leading to the cut-off valve. Sitting on our para- 

 chutes placed us too high to see well out of the windows, but all in 

 all it was an interesting trip. 



The Army had invested an immense amount of labor in preparing 

 the test plots where we were to make the experiments. Six plots were 

 laid out, each 1 mile long and 14 mile wide. They had to be separated 

 from each other by about 14 ^^li^® so that a spray could not be carried 

 from one plot to another by wind. Connecting the plots were well- 

 defined trails; around them and through them in crisscross arrange- 

 ment similar trails had been cut — through dense jungle. Such trails 

 were necessary because of the rough terrain, the dangerous black spines 

 borne by palms of a certain species, and the possibility that personnel 

 might become lost. Stakes had been set at regular intervals on the 

 plot boundaries and diagonals. As a result any of us could always 

 locate himself and go directly to and from his appointed station 

 without undue loss of time. 



Several sheets were spread on the ground within each plot that was 

 to be sprayed. This enabled us to count the insects that fell at 2-, 4-, 

 and 24-hour intervals after the spraying and identify them as to species. 

 Most of the species of insects were represented by only 1 to 5 speci- 

 mens each, but in the Diptera various species of Calliphoridae, Sar- 

 cophagidae, Tylidae, and Culicidae were obtained in much larger num- 

 bers. More than 50 individuals of each of several mosquito species and 

 more than 200 individuals of one were recovered. Specimens found on 

 the sheets represented 53 species of Coleoptera, including 16 species 

 of weevils, and 148 species of Diptera, including 10 species of blow- 

 flies (14). 



Casual observations of the insect populations in the jmigle indi- 

 cated no change in number or species of insects other than mosquitoes 

 after treatment. Occasionally large Lepidoptera and Hymenoptera 

 showing characteristic DDT poisoning were seen on the ground soon 

 after treatment. 



The Signal Corps' of the Army provided a ground-to-plane com- 

 munications system, which enabled occupants of planes to keep in 

 constant contact with men on the ground as they applied the spi'ays. 

 Smoke bombs and balloons were used to indicate plot boundaries to 

 men in planes. 



For estimating the mosquito population, we decided upon two 

 methods. The first was for 20 teams of 2 men each to count in each 



