398 MB. E. B. POULTON ON THE COLOUR-RELATION BETWEEN EXPOSED 
results of experiments in which the colours were only applied for a small part of the 
time during; which the larva is sensitive. 
O 
Experiments upon Vanessa atalanta. 
Series 1 .- —Four larvae of this species were kindly sent to me by Mr. H. L. Sure age, 
and on September 1 two of them were placed in a small glass cylinder surrounded 
and roofed with two layers of black tissue-paper, and with a black floor. One larva 
was a dark variety and probably in the stage before the last, while the other was 
a light variety and in the last stage. At the same time two other similar larvae—a 
dark and a light variety, both in the last stage—were placed in one compartment 
of the gilt box previously described. 
Sept. 2. The light-coloured larva in the dark had pupated some few hours. The 
other larva died. 
Sept. 4, 4.20 p.m. The light larva in the gilt box had just suspended itself to the 
roof. 
Sept. 5, 10.38 a.m. The light-coloured larva was pupating. Therefore Stage III. 
was almost exactly 18 hours in the case of this larva, both limits being obtained 
with unusual precision. The dark larva pupated subsequently. 
Series 2. —Mr. Surrage kindly sent me many other larvae of this species, and of 
these four nearly mature dark larvae were (September 10) placed in a small cylinder 
with a gilt roof and gilt background, extending round half of the internal circum¬ 
ference of the cylinder, the clear side being turned towards a strong light. 
On September 14 all had pupated, one upon the food-plant and three upon the 
roof. Stage III. was estimated at about 20 hours in one case, while in another it 
must have been at least 24 hours in duration. 
At about the same time a few other nearly mature larvae were placed in a 
darkened cylinder with black surroundings, and two pupae were obtained from this 
experiment. 
Three pupae were obtained from another set of larvae in a clear glass cylinder 
roofed with white muslin. 
Results. —Thus altogether 6 pupae were obtained in gilt surroundings, 3 in black, 
and 3 in clear glass with a white muslin roof. The 9 pupae of Series 2 were all 
compared together on September 30, while the 3 pupae of Series 1 had been 
compared much earlier and the imagines had emerged. The results, however, 
appeared to be very uniform. 
The pupae in the gilt surroundings were all very golden for this species, with the 
magnificent lateral triangular golden patch on the fourth abdominal segment, and 
with the four dorsal golden patches and sub-dorsal golden tubercles especially 
bright upon the metathorax and first abdominal segment. The most golden of the 
