98 Dr. G. B. Longstaff 07i 



backgrounds of sand-paper of various colours to imitate 

 natural backgrounds of sand or rock.] 



Admitting the fact of Heliutropism a third possible 

 explanation suggests itself. This special attitude exposes 

 not only wings, but the insect's body, most completely to 

 the sun's rays, and we may fairly suppose that such an 

 essentially sun-loving creature as a butterfly finds them 

 agreeable. To this explanation Dr. Dixey advances an at 

 least partial objection, viz.: that when the wings are closed 

 up both wings and body are least exposed to the sun's rays. 

 As the result of numerous observations made in Algeria 

 in February and March 1905, I satisfied myself that : 



Except early in the day, or when the sun is dull, 

 or when feeding on flowers, Fararge meo7ic, Or., 

 settles with the axis of the body tui-ned so that the 

 tail points more or less accurately to the sun, there- 

 fore when the wings are raised, in the attitude of 

 repose . . . the shadow is reduced to insignificant 

 dimensions.* 

 After somewhat intimate acquaintance with F. meone, 

 Or., in Algerin, it was pleasant, in May 1905, to study its 

 northern form P. a;geria, L., which is common in and about 

 my garden at Mortehoe, North Devon, and this was the 

 more pleasant because our butterfly is undeniably much 

 more beautiful than its southern sister. 



I have notes on ten specimens observed, and it may be 

 instructive to give them in detaik 



May 3. Observed two F. xrjcria ; one settled several 

 times with tail to the sun, the other was less 

 particular. 

 May 9. Saw a^n'm settled with wings open and tail 



directed towards the sun. 

 May 15. Saw one specimen of mgeria settle twice 

 with fairly accurate orientation ; another specimen 

 settled first accurately oriented ; then it settled 

 again with the body nearly at right angles to, but 

 with the head somewhat towards, the sun ; thirdly 

 it settled again at right angles, but with its head 

 turned to the opposite side. 

 May 19. Watched three specimens of mgeria and saw 

 each of them orient itself accurately twice. The 

 same day I saw another specimen orient itself four 

 times. 

 * Proceedings Eut. Sue. Lond., 1905, p. xxix. 



