1900.] IXSECTS OF THE " SKEAT EXPEDITION." 857 



centre and not towards the periphery ; but, nevertheless, it was 

 striking and, at a first glance, quite deceptive. When disturbed 

 the caterpillar commenced to walk along the leaf, slowly and 

 irresolutely, unbending and rebending its long thoracic limbs as 

 it moved, and shaking the two processes with which its abdomen 

 terminated. I took it home, and shut it up till the next morning 

 with a supply of leaves, hoping to photograph it when the light 

 was better. During the night the insect cast its skin, and in the 

 morning all likeness to anything else had left it. The skin was 

 no longer polished and glittering, and the colour had changed to 

 a dull brown with dingy white bars. Moreover, all sluggishness 

 of movement bad disappeared, and the caterpillar was now ex- 

 ceedingly brisk, behaving very much as a well-grown specimen of 

 our own English form would do. During the languor and 

 dangerous inactivity of the ecdysis and the period immediately 

 preceding it, protective coloration had been assumed ; as soon as 

 the operation had been safely performed, the habitual means of 

 defence were adopted once more. 



But to return to animals which, being otherwise inconspicuous, 

 have the power of exhibiting brilliant colour when alarmed. This 

 phenomenon is not only exemplified by insects. A good instance 

 is that of the Toad Callula pulclira, which is found not un- 

 commonly in the Siamese States, among the rubbish which collects 

 under the houses and in like situations. In this species, the upper 

 surface of which is otherwise of a warm brown colour, a broad 

 yellowish stripe runs along either side of the back ; but the 

 peculiar looseness of the skin and the folds into which it naturally 

 falls prevent this stripe from becoming conspicuous. When the 

 animal is disturbed, however, it draws air into its lungs until its 

 body becomes almost globular, and the skin is stretched in such 

 a way that its contrasting colours are displayed to their best 

 advantage. We may compare this amphibian to the fish of the 

 genus Tetrodon and others, which have earned the name of 

 Balloon-fish among Europeans, and of "Ikan bunted" or Pillow-fish, 

 among Malays, by the manner in which they gulp down air into 

 their stomachs, so causing the brilliant coloration of many of 

 them to become conspicuous, and also the spines with which they 

 are armed to be erected. 



Another interesting example is afforded by the Lizard Liohpis 

 bellii, which the Malays call " Biawak Pasir " 1 , or Sand Monitor, 

 and which is common in all sandy plains where the vegetation is 

 scanty in the north of the Malay Peninsula. The male of Liolepis 

 is coloured in what sounds a very gorgeous fashion, and what is 

 in nature by no means a conspicuous one. The upper surface is 

 grey, mottled and eyed with green, the lower surface pale yellow 

 veined with blue, which is more conspicuous on the underside of 

 the thighs and the neck than on the rest of the body. Along each 

 side there are a number of transverse bars, alternately of orange 



1 "Biawak" is the Malay name of Varanus. 



