Aug. X 5 , X93X 
Dispersion of Flies by Flight 
749 
Table VI. —Third dispersion test at Dallas, Tex. Species and sex of marked flies recovered 
in different directions from point of liberation 
Trap 
No. 
Dis¬ 
tance 
from 
place 
of re¬ 
lease. 
Musca domestica. 
Chrysomya macel- 
laria. 
Ophyra aenes- 
ce.ns. 
Total. 
Grand 
total 
(num¬ 
ber). 
Num¬ 
ber. 
Per cent. 
Num¬ 
ber. 
Per cent. 
Num¬ 
ber. 
Per 
cent. 
Num¬ 
ber. 
Per cent. 
Miles. 
c? 
9 
cT 
9 
c? 
9 
9 
d 
9 
d 
9 
d 
9 
d 
9 
1 W.... 
4. 5 
1 
2 
67.0 
5 
43 
89. 6 
6 
45 
11. 8 
88. 2 
51 
2 W.... 
6. 0 
0 
I 
00 
100.0 
20 
4. 8 
1 
21 
4. 5 
os. s 
22 
3 w.... 
7.0 
0 
2 
00 
IOO- 0 
0 
4 
0 
0 
6 
0 
IOO. 0 
6 
4W.... 
8.1 
0 
3 
00 
IOO. 0 
0 
8 
0 
IOO. 0 
0 
0 
0 
11 
0 
IOO. 0 
11 
T< 
>tal... 
1 
8 
11. 2 
88.8 
6 
75 
7-4 
92. 6 
0 
0 
7 
83 
7.8 
92. 2 
90 
iN,... 
4.1 
0 
IS 
00 
IOO. 0 
6 
32 
15-8 
84. 2 
2 
2 
50 
50 
8 
49 
14. 04 
85.96 
57 
2 N.... 
5* 6 
3 
10 
23 
77.0 
0 
7 
17 
15. 0 
85. 0 
20 
3 N.... 
6. 3 
2 
40 
60. 0 
5 
4 N.... 
7.8 
0 
0 
3 
25 
10. 7 
89-3 
0 
0 
3 
25 
10. 7 
89- 3 
28 
T< 
>tal... 
5 
28 
15 - IS 
84- 85 
9 
64 
12.3 
87-7 
2 
2 
50 
50 
16 
94 
14 . 55 
85- 45 
no 
1 E. 
4. 7 
0 
8 
8 
7 S. 8 
33 
2 E. 
6. 2 
0 
0 
13 
3 E. 
7. 2 
1 
25 
75. 0 
6 
10 
4 E..... 
8.0 
0 
2 
00 
IOO. 0 
0 
5 
0 
IOO. 0 
0 
0 
0 
7 
0 
IOO. 0 
7 
Tr 
>tal... 
7 
12.5 
87 ’ 5 
,8 
47 
14-5 
85 - 5 
0 
0 
9 
54 
14-3 
85-7 
63 
iS. 
4. 6 
I 
9 
10. 0 
89. 6 
48 
jS. 
6. 1 
I 
8 
11. 2 
88. 8 
l8 
t8. 2 
81. 8 
22 
3S. 
7 - 3 
O 
0 
4vS. 
8. 2 
O 
0 
. 2 
7 
22. 3 
77 - 7 
0 
0 
2 
7 
22.3 
77 - 7 
9 
Tc 
)tal... 
2 
17 
10. 6 
89.4 
9 
54 
14-3 
85- 7 
0 
0 
11 
7 i 
13-4 
86.6 
82 
Grand 
total.. 
9 
60 
13.04 
86. 96 
32 
240 
11. 76 
88. 24 
2 
2 
50 
5 ° 
43 
302 
12. 44 
87. 56 
345 
DIRECTION OF fught 
In Table VI the numbers of marked flies recovered in the different 
directions from the point of liberation are set forth. In considering 
the house fly from the standpoint of the direction of travel as indicated 
by the number of marked specimens recovered, probably the most strik¬ 
ing fact is that 33, or 47.8 per cent, of the marked flies were taken in the 
four traps to the north of the point of release, and the next largest num¬ 
ber—19, or 27.5 per cent—were recovered in the traps in the opposite 
direction. The catches to the west and east were almost identical, the 
west with 9 flies, or 13 per cent, and the east with 8 flies, or 11.6 per 
cent. 
In considering the factors which might influence dissemination of the 
house fly we immediately think of the attraction of feeding and breeding 
places, the character and amount of travel along the highways, and the 
direction and velocity of the wind. The attraction of odors from towns 
and cities would tend to favor the migration to the north and south, 
since there are several towns located along the north line of traps and a 
few to the south and east. If the flies are inclined to go toward odors 
borne a considerable distance on the wind, one would expect a greater 
number to the south, since the volume of odors from the city of Dallas 
