REACTIONS TO LIGHT AND GRAVITY IN DROSOPHILA 81 
TABLE 14 
BEFORE WING REMOVAL AFTER WING REMOVAL 
id Light Gear tice) bight (vertical) 
Male | Female; Male | Female} Male | Female} Male | Female 
1 96.6 | 98.3 | 68.3 | 77.5 
Groupee see 2 | 96.6 66.6 41.6 50.0 
ie eas 5.8 45.0 
Memperagunrese ese ashe 23 .5° 230 Ow 
1 98.3] 99.1] 67.5) 64.1 
Croupsbe eee. 2 97.5 55.0} 52.5 91.6 
3 35.8 | 10.1 | 80.0) 42.5 
Memperaturesseeesse sear 2B) ay 23nou 
Groupe.) he | 1 | 84.1] 94.1] 35.01 25.8 | | 
Memperature.. st se. 7456 24° 24° 
otal seas eee ee ee | etn Gl oso) Ol) 2374) 222.4 OAR Ie oleic GAG 92zo) 
AWVETAPES eas eee Oon9| 90.2! (S98) 5 Gales 2.8) Waree2 | 40 ne 
more data. It is true that a somewhat similar tendency is man- 
ifest among the males in table 9, but the poor light arrangement 
in the earlier experiments makes the records of doubtful validity 
on this particular point. 
Let us now consider the reactions of vestigial flies. Three 
groups of insects, half male and half female, were kept for the 
usual length of time after hatching, and then subjected to the 
test just described for wild flies. The only difference was that 
in this case the single lamp was used in the gravity trials. As 
will appear from the results, however, this feature was of no 
consequence in this instance because the insects were only very 
slightly phototropic. Also since the wings were already only 
stubs, nothing was cut off. Table 15 summarizes the results. 
Strap stock was next tested. Three groups, constituted asin 
vestigial and wild were kept as usual till 5 days old. The only 
irregularity in this connection was the use of only nine instead 
of ten females in Group A. As to the apparatus, the single 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 25, NO. 1 
