THE LIFE-CYCLE OF MOlIsA EECTIEOSTEIS. 
n21 
Isolated females in an ice chest at about 5°.C. gave 5'4 per 
cent, males, when crowded together 42’5 per cent. 
(4) The intensity of crowding’, measured by the number of 
parents kept together in the same glass, is shown to have a 
not very constant effect on the proportions of males pro- 
duced, on the whole the proportion of males increasing with 
the intensity of crowding. 
(5) The influence of isolation and of a high temperature on 
the suppression of the sexual forms may be ascribed either to 
the comparative absence of excretory matter under these 
conditions, or else to the nutritive conditions being under 
these circumstances highly favourable. 
Table I. — Number of Males and Females in Broods 
produced at Different Temperatures in Indi- 
vidual lines. 
Line. 
Isolated. 
Crowded. 
1 
i 
H. 
R. 
c. 
H. 
R. 
c. 
cj8. 
9 s. 
6s. 
9s. 
<Js. 
9 s. 
<Js. 9 s. 
(Js. 
9 s. 
Js. 
9 s. 
215 
58 
174 
63 291 
282 
290 
28 
0°/o 
25°/o 
17-7°/ 0 
49-3°/, 
O/o 
— 
: 3. 
— 
28 
25 
— 
— 

12 
22 
— 
1 
52-8°/o 
1 
1 
35-2°/„ 
4. 
— 
— 
8 
57 
— 
— 
— ^ — 
122 
127 
13 
15 
1 
12-3°/o 
48-9°/, 
46-4°/, 
1 5. 
— 
419 
— 
24 
1 
153 
2 73 
36 
35 
— 
11 
0"/o 
0 °/o 
■5°/o 
2-67o 
50-7°/, 
07o 
i 
— 
78 
567 
4 
4 

592 
405 
41 
50 
1 
12-l°/o 
50°/o 
59-3°/, 
45°/o 
7. 
— 
98 
58 
145 
— 

151 
191 
28 
16 
1 
0°/o 
28-5°/o 
44-1 
63.3°/, 
62 
8 
54 
— 
— 
86 — 
63 
160 
— 
1 
0°/o 
12-9=/o 
100 
28-2°/, 
10. 
87 
65 
130 
— 

313 
134 
1 
0°/o 
33-3°/„ 
70°/, 
11. 
286 
2 
159 
— 
— 
41 199 
54 
123 
76 
79' 
j 
0°/o 
l-2°/o 
17-1°/ 
30-5°/, 
497o 
1 
12. 
— 
18 
50 
5 
17 
94 94 
6 
— 
9 
27i 
1 
26-5°/o 
21-7"/o 
50°/, 
100°, 
36°/, 
i 
1 
Total 
0 
0°/o 
1167 
323 
19-l°/o 
1385 
10 
5-4 °/o 
174 
286 657 
30-3°/, 
1631 
52-3°', 
1487 
167 '226 
42-5°/, 
