HELIOTKOPISM 
541 
I quote two cases from my notes :—* 
Feb. 8, Guyotville. Watched a specimen settle about twenty 
times. The wings were always at first expanded about three- 
fourths, an adjustment of its position was in most cases made 
immediately, and after that the wings were raised over the 
back. In about twelve individuals the orientation was perfect 
and the shadow a minimum; in seven or eight the orienta¬ 
tion was imperfect, with a maximum error of about 45°, but 
usually much less. 
Feb. 25, Biskra. Watched one settle three or four times, always 
with a shadow near the minimum. 
Only one specimen of P. meone was ever seen to settle facing 
the sun ; it did so three times, a fourth time turning its tail 
in the usual way. This was at Biskra on March 5th, and I 
noted at the time that the sun was not shining strongly. Two 
only were observed to settle with the axis of the body at right 
angles to the sun. One of these appeared to be crippled in the 
legs, since it alone always leaned to the same side. A third 
specimen, feeding on Laurustinus flower in the Chabet Gorge 
on March 18th, did not appear to orient itself by the sun. 
In conclusion, except early in the day, or when the sun is dull, 
or when feeding on flowers, P. meone settles with the axis of the 
body turned so that its tail points more or less accurately to the 
sun; therefore, when the wings are raised, in the attitude of 
repose (as is more common towards the afternoon), the shadow 
is reduced to insignificant dimensions. 
Pyrameis cardui , Linn., is an abundant butterfly in Algeria. It 
is not so easy to watch as P. meone , for it is a strong flyer and 
much more wary ; moreover, many of the specimens were seen in 
exposed places during windy weather. Nevertheless, I can say 
confidently that it generally settles with its tail to the sun, 
though it does not do this with the regularity of meone . I saw 
two specimens turn their heads to the sun, and a third settle 
twice with its body axis at right angles, though the third 
time it settled normally. The first two freshly-emerged 
specimens, at Hammam R’ihra, March 25th, did not orient as 
well as those that had hybernated. 
These observations confirm those of Professor G. H. Parker, on 
Vanessa antiopa, Linn., and on a G-rapta in the United States, 
and supply a reason for the habit that does not appear to have 
occurred to him, namely, concealment when in repose. 1 
1 Proc. Ent. Soc. Lond ,. 1905, pp. xxviii-xxix. 
