1915.] 611 
Lutz, Experiments with Drosophila ampelophila. 
fast conclusions along certain definite lines. They do, however, demon- 
strate once more that natural selection does exist and that it influences 
mean, variability and correlation. Much as we would like to have explana- 
tions, the facts are, at present, the important things. 
TABLES OF Data. 
Throughout, the units for the egg-larval and pupal periods are days. 
The units for length of adult life are days in the “normal” experiments 
and hours in the starvation experiments. The units for the wing measure- 
ments are divisions on an arbitrary micrometer scale. 
Egg-Larval Period 
Ld Be 6S Lari Baa et a Eade ak ade 1 od 
oe a pana ee ett et ee BaD, AD ccs ade SM ahs nce amet ba 6 
10 Wie eee CNG ls Et ah ae ae oer ie a 13 
15 awe eh aS me ie ey ele 1 29 
20 |. DANE ie crate Ger ae Cle eae We ks 27 
95° 3 15 ee Ne oe 2 ears cs 1 23 
30 | J Maltee Saha Mipils ooee echo toe 32 
BBL oe ei ee a aes 49 
=| 40— ee ae Fay at em 1 24 
cee wes ce ae ie aes Re au 2 
E| 50 _ ls one pe kore oF 6 
vig ee Pe ah oe aise R onan eee eee: hoe ee 
60 te On Saree ee: hear 3 
BB ta. de a ee eo eee ee og 2 
70 Ae ee | fa SN AD ae 8 
fp Ome ee ers a eee eee 8 
80 Be RRS Hee leer es Gad ea eee 6 
ie baie Bae ey Wein ont ae 5 
90 Mie creer mee Sas : 1 
1 | 69 | 45 liga rao Ba A meme lien lames ts 1 Fs) 280 
Table 5. Data for males concerning correlation between the Duration of the 
Egg-Larval Period and Normal Length of Adult Life. 
