Aug. is, 1921 
Dispersion of Flies by Flight 
733 
packing houses; traps No. 14 to 18, inclusive, 3,076 feet 5 0 north of west 
within the inclosure of another large packing house. To make traps No. 
2 and 3 still more attractive to blowflies a large amount of meat waste 
was hauled out into the field between them and partially plowed under. 
A creek fringed with trees flows nearly north between the point of 
liberation and the packing houses, about 1,100 feet from the point of 
liberation; thus the flies, in order to reach traps No. 4 to 18, inclusive, 
would have to cross this stream. The closest road with any considerable 
amount of travel is about 1,400 feet from the point of liberation, passing 
near traps No. 5 to 13 and turning north at right angles near trap No. 4. 
Almost immediately after release two colored screw-worm flies 
(Chrysomya macellaria Fab.) were observed at trap No. 1, and several 
were seen about the rendering plant at trap No. 2. About three hours 
after liberation a marked C. macellaria was observed through the screen 
in trap No. 5. 
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Fig. i. Diagram of dispersion test at Fort Worth, Tex., indicating relation of recovery traps to point 
of release. 
June 1, 11.45 a - m.> flies in traps No. io to 13, inclusive, were killed 
and examined and the following marked flies found: Trap No. xo, 1 9 
Phormia regina (the black blowfly), 1 9 Chrysomya macellaria; No. 11, 
x 9 P. regina; No. 12, 1 9 P. regina; No. 13, 2 9 P. regina, 1 9 C. 
macellaria. June 1, between 2 and 3.45 p. m., the following colored 
flies were found in traps No. 1 to 9, inclusive: No. 1, 2 <j and 16 9 
P. regina, 1 9 C. macellaria, 5 9 Musca domestica (house fly); No. 2, 
9 P. regina, x 9 M . domestica; No. 3,1 <5 and 5 9 P• regina-, 3 9 
C. macellaria, 5 9 M. domestica; No. 4, 2 <? and 9 9 P. regina, 2 9 
C. macellaria, 2 9 M. domestica; No. 5, 6 9 P. regina, 3 (2 9, 1?) 
C. macellaria. No. 6, 7, 8, 9, none. June 2, 9.45 to 11.20 a. in., No. 
14 to 18 contained the following colored flies: 4 9 P. regina, 2 9 C. 
macellaria, 1 9 M. domestica. June 2, 12.30 to 2 p. m., flies in No. 
5 to 13, inclusive, were killed and examined, and the following marked 
specimens were found: No. 5, 4 9 P. regina, 1 9 C. macellaria; No. 6, 
1 9 M. domestica; No. 7, none; No. 8, 2 9 P. regina; No. 9, none; 
