740 
Journal of Agricultural Research 
Vol. XXI, Mo. io 
normally nondomestic, we would not expect the same distribution of these 
species as of the house fly, yet the proportions caught in different direc¬ 
tions are very similar. 
Table III .—Climatological data relating to first and second dispersion tests at Dallas , 
Tex. 
Temperature. 
Wind. 
Humidity. 
Act¬ 
ual 
sun. 
Date. 
Max. 
Min. 
Mean. 
Direction during successive 
hours from 6 a. m. to 8 p. m. 
Velocity 
during 
day. 
Rain. 
Max. 
Min. 
Mean. 
1916. 
June 29 
0 F . 
89 
0 F . 
70 
0 F . 
80 
4 SE-, zo E. 
M iles. 
7 to 14 
Inch. 
0 
Per 
cent. 
87 
Per 
cent. 
55 
Per 
cent. 
7 i 
Per 
cent. 
100 
30 
93 
74 
83-5 
io S., 4 E. 
10 to 13 
0 
85 
47 
66 
88 
July 1 
93 
70 
81.5 
3SE..3S, aSW., 2E..4SE... 
4 to 10 
0 
84 
40 
62 
97 
2 
92 
73 
82.5 
2 E., 12 SE.,. 
2 to 8 
0 
80 
48 
64 
7a 
3 
93 
72 
82.5 
2 SE., 3 S., 4 SE., s E. 
3 to 13 
0 
78 
44 
61 
90 
4 
94 
73 
83-5 
2 E.. 1 S., 1 SW. f 5 E., a SW., 
2 to 15 
.07 
83 
47 
65 
67 
5 
92 
74 
83-0 
3 E. 
3 N., 8 NE., 3 N. 
5 to 14 
0 
77 
49 
63 
73 
6 
93 
74 
83.5 
aNW.,3 N., 6NW..3 N. 
4 to 10 
0 
68 
36 
5 * 
86 
7 
96 
75 
85*5 
3 W., aN., 4 NW., 5 N. 
2 tO 12 
0 
78 
45 
61 
97 
8 
96 
73 
84* 5 
2 N., 5 E., 5 N., 2 NE. 
2 tO II 
0 
72 
36 
54 
93 
9 
96 
73 
84-5 
6 NW ..3 W.,sNE. 
3 to IO 
0 
74 
29 
51 
89 
zo 
99 j 
74 
86.5 
2NW., 4 SE.,sW.,3E. 
2 SE., 4 SW.,sSE., 3 S. 
2 tO 7 
0 
74 
34 
49 
100 
XI 
98 
77 
87-5 
2 tO II 
T 
69 
30 
49 
86 
za 
95 
78 
86. S 
13 S., i SE. 
5 to 13 
0 
68 
34 
51 
78 
*3 
95 
77 
86.0 
2 SE., 12 S. 
4 to ii 
0 
63 
4 i 
5 ^ 
7 i 
14 
95 
78 
86.3 
2 S., 3 SW., 2 S., 7 SE. 
5 to 11 
0 
64 
38 
51 
75 
IS 
97 
77 
87.0 
aSW.,3 W.,iS.,SSE. 
3 to 7 
0 
68 
43 
55 
89 
16 
IOI 
77 
8g. 0 
2 NW., 3 W., 4 S., 3 SE. 
4 to 14 
0 
62 
33 
47 
74 
17 
97 
75 
86.0 
a E., 1 SE., 1 S., 10 E. 
2 to II 
0 
85 
48 
66 
79 
18 
98 
77 
87-5 
1 E..6SE., iS., 6SE. 
4 to 10 
0 
85 
35 
60 
89 
19 
99 
76 
87.5 
4 SE., 3 E., 1 SE.. 6 E. 
5 to 14 
0 
80 
36 
58 
84 
20 
95 
76 
85-5 
3 NE..sNW.,3 W..3N. 
5 to 12 
T 
80 
49 
64 
60 
21 
95 
76 
85-5 
5 NE., 1 E., 3 N., 5 NE. 
5 to 11 
T 
79 
1:0 
64 
65 
22 
97 
75 
86.0 
3 NW.,iSW.,iN.,8NE. 
3 to 11 
0 
78 
38 
58 
100 
23 
97 
79 
88.0 
9E..5NE. 
3 to II 
0 
76 
48 
62 
99 
24 
95 
76 
85-5 
2 NE., 3 E., 9 NE. 
4 to 13 
0 
60 
39 
49 
94 
25 
96 
76 
86.0 
1 NE., 6 E., 1 NE.. 6 E. 
9 E., 1 SE., 2 E., 2 SE. 
5 to 17 
0 
60 
31 
45 
88 
26 
88 
72 
80. 0 
4 to 17 
.19 
98 
85 
9 i 
48 
RELATION OF SEX TO DISPERSION 
Unfortunately the percentage of males and females among the flies 
liberated was not determined, hence no information can be gained from 
this test as to the relative proportion of the sexes among the flies recov¬ 
ered. It will be noted (Table II) that in the first ring of traps about the 
point of liberation 88 per cent of the marked house flies taken were 
females and 63.2 per cent of the screw-worm flies were females. In the 
second ring of traps the percentages of females of these two species were 
92.8 per cent and 70.7 per cent, respectively; in the third ring 92.8 
per cent and 78.3 per cent, and in the fourth ring 90.4 per cent and 75.5 
per cent. So few marked flies of the other species were recovered that 
the sex data on them will not be discussed separately. It is noted that 
among the 4,652 marked flies recovered 3,952 were females, or 84.9 per 
cent. It might be supposed that if dissemination is induced largely by 
instinctive search for food and places to oviposit the females might tend 
to travel farther than the males, but the foregoing figures hardly justify 
