LIST AND SHADOW 
559 
Mortehoe, July 20th,1906. E.janira. Four specimens oriented; of 
these, three had the wings open, one closed. Eleven specimens 
were settled across the sun, with wings closed ; certainly one of 
the latter listed from the sun. 
Mortehoe, July 30th. Some noticed to orient; others sitting across 
the sun. 
Mortehoe, August 11th, 1907. One ^ and two ? oriented; wings 
three-quarters open. Others were seen across the sun and one of 
these listed. The wind was, however, this day too strong for 
trustworthy observations. The butterflies mostly sat head to 
the wind. 
Mortehoe, August 15th, 1907. Several specimens noted settled on 
grass, on or near the ground. Of these three oriented, one 
with the wings quite open, the other two three-quarters open. 
A $ oriented with the wings open; another $ settled on a leaf 
oriented with the wings three-quarters open. Another ? sat 
across the sun, had its wings up, and listed away from the sun. 
The eye-spot on the fore-wing was sometimes obscured, sometimes 
in part visible. 
Mortehoe, August 16th, 1907. A 9 seen to settle three times across 
the sun, with its wings closed, leaning away from the sun. Yet 
another 9 was seen to settle three times ; twice across the sun, 
with wings closed, but on the third occasion with its wings open 
and fairly oriented. 
Mortehoe, August 22nd, 1907. A 9 observed to settle three times, 
(1) oriented; (2) across, with slight list away from the sun; 
(3) oriented. 
Mortehoe, August 24th. A $ settled on a leaf oriented. 
The effect of a list on the shadow . 
It is worth while carefully considering the precise effect of a list 
on the shadow of a butterfly sitting with the axis of its body at right 
angles to the sun’s rays. 
To make the matter clear I have constructed three diagrams. 
The diagrammatic butterfly is in each figure supposed to be settled 
with its tail towards the observer, but turned somewhat to the left 
so as (in two of the three diagrams) to expose the underside of the 
right wings obliquely to the observer. The sun is supposed to be to 
the right of the observer and nearly to the right of the butterfly. 
The sun’s elevation is taken to be 50°, representing a condition that 
