40 EXPERIMENTS WITH DROSOPHILA AMPELOPHILA. 
TABLE 37.—Mean wing-dimensions at various periods of continued disuse. 
| Generations of disuse. Length of wing. | Breadth of wing. Length * breadth. 
| Be pnb ET 
| lstatOnahGesr cer scevacke 67.00+ 0.12 | 32.55+ 0.07 2223.12 + 8.85 
[PTH ROMO Ely ccsts.n.- 266 550)== OSE se .60l=) 0206 22 Caleta 
OOLOLCOV ONG e se ne.ces |) GAO 0126) B98 3-10.06 2115.44 = 7.42 
AVSt LO Mordeccesccessss | 67.67 + 0.18 | 84.06 + 0.08 2358.94 + 11.46 | 
| | 
If the experiment had stopped at the end of the thirty-fifth generation 
it would have appeared from this table that the wings were actually 
getting smaller, since the area, as judged by length < breadth, was 
smaller in the second lot than in the first, and still smaller in the third— 
the difference being nearly ten times the expected error. However, this 
would have been a hasty conclusion. The fourth lot is as much larger 
than the first as the third is smaller. So we must conclude that there 
is no evidence that the constant disuse of the wings during more than 
40 generations has had any effect. 
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