440 Proceedings of the Royal Physical Society. 



took measures accordingly. It would have been quite 

 impossible to mistake the shadow for that of a stick ; no 

 stick has six little twiglets arranged symmetrically round 

 it and supporting it wherever it may chance to fall. 



Except for slight movements of the antennae, the Phasmids 

 remained quite still on the leaf; I was never able to see 

 them feed. If they were disturbed in any way, however, 

 they immediately dropped to the ground and made their 

 escape among the long grass and undergrowth. They were 

 able to walk with considerable speed, though their gait was 

 awkward and stilted. I was quite unable to discover what 

 became of them at night, for I never found them on the 

 leaves either late in the afternoon or early in the morning. 

 Most probably they remained concealed among the under- 

 growth except during the heat of the day. The only 

 specimen which I obtained away from the clearing on 

 Bukit Besar was captured on the ground in deep jungle, 

 one morning in the beginning of September. Even on the 

 jungle floor it was not very inconspicuous, as its colour was 

 too uniform, and it betrayed itself completely by walking 

 about at its fastest speed. 



Bemarks. — There are many animals which might be said 

 to be protectively coloured, were they found habitually 

 among the objects that they resemble. For instance, the 

 larva of a common Malayan bug (Mattiphus sp. (?)) is 

 flat and somewhat leaf-like in shape, and in colour har- 

 monises exactly with the peculiar pink of the young leaves 

 of many seedlings. Sometimes a specimen of this larva 

 chances to stray among such leaves, and then appears to be 

 protectively coloured, being very hard to detect, by the 

 sense of sight only, in such surroundings. But its usual 

 position is on stones, and in other situations in which it is 

 conspicuous. It is an active insect, provided with well- 

 developed stink-glands, and has apparently no need to 

 conceal itself, supposing that it were possible for it to do 

 so. Its likeness to the leaves is, it seems, a chance one, 

 and has no bearing, as far as we can see, on any theory 

 in particular. The Phasmid, however, is only conspicuous 

 at certain times of day, when the sun is at its hottest and 



