LIST AND SHADOW 
561 
But as a matter of fact, the list has almost always been observed 
to be away from the sun. Such a list increases the length of the 
shadow until the list amounts to 40° (under the conditions assumed) 
and so brings the wings into a position normal to the sun’s rays 
(see Fig. 18). The length of the shadow is then at its maximum 
and longer than the wings. 
A further list would diminish the shadow until, when the wings 
touched the ground, it would equal their length. 
A little consideration will, however, show that by listing the 
butterfly, so to say, covers up its own shadow more and more, so 
that while a slight list produces little effect on the shadow, a con¬ 
siderable list—45° and upwards—would make the shadow less 
conspicuous than that cast by the same butterfly in the upright 
position. 
Fig. 18.—Shadow of butterfly—listing 40° from sun. 
My conclusion accordingly is that, so far as regards the shadow 
cast, no list from the sun can be protective to the insect unless it be 
extreme. Again, a list from the sun, by resulting in the maximum 
illumination of the wing surface, can hardly aid concealment. At 
the same time, it cannot be denied that a butterfly by placing itself 
out of the upright, may thereby be protected in so far as it may then 
he more difficult to detach it from its surroundings. This would 
certainly appear to have been the case with the Melanitis recorded by 
Col. Bingham and by “ E. H. A.,” also with the S. semele observed by 
Mr. Waddilove. 
Barrett’s remark as to a rarer British butterfly, Grajpta c-album, 
Linn., deserves quotation :— 
“. . . fond of sunning itself in roads, on warm walls, or on 
the ground upon dead leaves in sheltered valleys. Here if the 
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