( xxviii ) 



position with their heads directly away from the sun in order 

 to receive as much heat as possible, the speaker wished to point 

 out, that when the wings are raised over the back, this was 

 the very position which insured a minimum of heat. The size 

 of the shadow cast is a criterion of the amount of heat inter- 

 cejited and in this position with the wings upright the shadow 

 becomes a mere line. When tlie wings of a butterfly resting 

 in this position on the ground are fully opened, there is, it is 

 true, some very slight compensating gain of heat, wherever 

 the sun's rays strike the earth obliquely. The head of the 

 buttei'fly being turned from the sun, the raised costal margins 

 of its fore-wings insure that the heat rays strike the plane of 

 the wings with slightly less obli(pxity and therefore with more 

 thermal effect than they do the ground. 



Referring to the "list" of butterflies in the resting position 

 Professor Poulton said that, on one occasion many years ago, 

 he had obseived this movement in a pronounced degree in the 

 Green Hairstreak (Thecla rubi). The butterfly was observed 

 at rest on the flat surface of a leaf at Birdlip, Gloucestershire, 

 and it let itself down on one side so completely that it seemed 

 to lie flat on the leaf. The obliteration of shadow was very 

 marked and had at the time forced itself upon the speakei-'s 

 mind as the significance of the attitude. 



Dr. F. A. DiXBY said that he was much struck with the fact 

 pointed out by Dr. Longstaff, that there were several hours of 

 daylight during which most butterflies were inactive, and were 



.... Too late or too early in tlie day, it was impossible to see a single 

 stiek-insect in the cleariug ; and during my six months' stay in Lower 

 Siam, I never was able to discover any Phasmidie of any species late in the 

 afternoon." Mr. Annadale liowever found a single specimen in the early 

 morning clinging motionless, like an enormous Geometrid larva, to a blade 

 of grass, and remaining "absolutely still while the grass was broken otl". " 

 Towards the end of the paper Mr. Annandale describes the habits of a 

 flower-like beetle-larva (a^iparently an Endomychid), which, " early in the 

 morning, as late as two hours after sunrise (which occurs in Patalung 

 between five and si.x o'clock)," rests "motionless in the angle formed by 

 the leaves with the stem " of its favourite plant. These same larvce are, 

 he states, extremely active during the heat of the day. As possibly bearing 

 upon these habits the author remarks that " The hour immediately pre- 

 ceding and following upon sunrise is the time of the greatest activity of 

 many Malayan animals, for both nocturnal and diurnal species are often 

 then at work." At the same time, Mr. Annandale is careful to point out 

 that nothing is "known as to the enemies and dang.'rs to which this 

 particular insect is exposed." [E. B. P.] 



