550 
BIONOMIC NOTES 
contemplates a long stay (as at night, or when the sun goes behind 
clouds) the closed-up attitude is adopted to take advantage of its 
cryptic colouring, and not to minimize its shadow. 
The other observations were made on Belenois severina, Cram., a 
white butterfly that we found very abundant at Durban. 
Dr. Dixey says :— 
B . severina, g and ?; when clouds come over the sun, this 
species generally settles on a grass stem, and, closing its 
wings tightly, becomes part of the picture. It certainly 
generally turns its back to the sun when it settles in sun¬ 
shine, and then does not often close up its wings. 
My note is as follows :— 
B. severina, 2 <j> seen to settle across the sun, early in the day. 
Late in the afternoon many <£ severina seen settled with 
wings three-quarters open, and tail more or less to the sun ; 
but where much exposed to wind the wings were closed 
and the head turned to the wind, so as to be almost across 
the sun. 
It is worthy of remark that throughout all these observations of 
heliotropism, I cannot recall a single case in which an adjustment, 
or subsequent movement of the butterfly after pitching, tended to 
throw it out of orientation. Hence it is fair to assume that if the 
insects had been watched longer after pitching positive results would 
have been observed in a larger proportion of cases. 
But, be that as it may, beyond doubt it is a habit with a number 
of butterflies, especially Nymphalines, to settle with their tails to 
the sun. Whether they do this, as Professor Parker supposes, to 
display their charms to the greatest advantage, or whether the first 
impulse was given by the light or warmth of the sun's rays, I am 
unable to determine, but that in such species as Bararge megaera 
soils is at the present day so much more common in tropical than in temperate 
regions that it may almost be regarded as a characteristic of a hot climate.”— 
Geological Magazine , 1900, p. 564. 
Again, Mr. J. J. H. Teall, F.R.S., speaking of the Keuper Marl, etc., at Sidmouth, 
said that he thought “ that the red colour of the formation was mainly due to the 
sub-aerial decomposition of rocks containing ferriferous compounds, under conditions 
similar to those prevailing at the present day in India, the Southern States of 
Eastern North America, Brazil, and parts of Africa, in short, to what might be 
termed the lateritic type of decomposition. Under this mode of decomposition the 
iron becomes oxidized, and deposited as a coating on the grains of quartz and other 
undecomposed minerals. The red material thus produced would mantle the slopes, 
fill up the hollows, or be spread out as flat fans over the low ground by torrential 
action. It would also be deposited in lakes, lagoons, or seas .”—Proceedings of the 
Geologists' Association , July, 1899, p. 141. 
