HELIOTROPISM 
543 
has sugared regularly in the same place has not observed among 
common Noctuae some individuals bolder and greedier than others ? 
I often saw meone settle on sandy roads, rocks, or walls, but the 
aegeria here referred to were for the most part settled on leaves, and 
the question of protection by economy of shadow could scarcely arise 
in their case. 
The next subject of observation was Pararge megaera , Linn., 
which was especially interesting to me as nearly allied to P. 
schahra , the common Himalayan butterfly in which I first noted 
heliotropism in October, 1903. 1 The spring brood was not so 
numerous as the summer brood usually is, and only ten specimens 
were noted settled. Of these the first, a female, was watched on a 
Devonshire “ dry ditch,” settling for the most part on the rough 
slates of which it was built, that is to say, on surfaces not always 
well adapted for precise orientation. It was, however, observed to 
settle several times with its tail to the sun, and on one of these 
occasions it raised its wings over its back so that its shadow was 
scarcely visible, but two or three times it settled at right angles to 
the sun. Six other specimens were observed with their wings open, 
settled for the most part on flat ground, and all correctly oriented 
(one observed twice). Another specimen was first seen settled on 
the flowers of Potentilla tormentilla, Sibth., at right angles to the 
sun, but afterwards on Scilla nutans , Sm., correctly oriented. Yet 
two other megaera were seen settled, one on the road, the other on a 
flat stone, both with their wings closed up, correctly oriented, so as 
to throw practically no shadow. 
The following note may be added:— 
Mortehoe, September 14, 1907, late afternoon. P. megaera found 
asleep upon the face of a rock, about 3 feet above ground: its 
head up, antennae porrected but separated; wings in close con¬ 
tact; fore-wings drawn back so that no fulvous colour was exposed. 
Mortehoe, August 24, 1911, 5 p.m. P. megaera at rest on a rock in 
deep shade. Attitude as in last paragraph. 
Epinephele tithonus, Linn.—The following observations show that 
the habits of this butterfly, as regards orientation, are similar to those 
of Pararge megaera :— 
Mortehoe, July 20, 1906. A specimen observed settled across the 
sun, with wings closed. 
Same place and day. Another specimen seen to settle twice; 
oriented, with wings open. 
1 Trans. Ent. Soc. Lond. } 1905, p. 67. 
