92 TROPICAL NATURE, AND OTHER ESSAYS. 



resemble the foliage among which they live, and as they 

 sit quite motionless, they are not easily perceived. 



The Phasmidae are perfectly inoffensive leaf-eating in- 

 sects of very varied forms ; some being broad and leaf-like, 

 while others are long and cylindrical so as to resemble 

 sticks, whence they are often called walking-stick insects. 

 The imitative resemblance of some of these insects to the 

 plants on which they live is marvellous. The true leaf- 

 insects of the East, forming the genus Phyllium, are the 

 size of a moderate leaf, which their large wing-covers 

 and the dilated margins of the head, thorax and legs 

 cause them exactly to resemble. The veining of the 

 wings, and their green tint, exactly corresponds to that of 

 the leaves of their food-plant ; and as they rest motion- 

 less during the day, only feeding at night, they the more 

 easily escape detection. In Java they are often kept 

 alive on a branch of the guava tree ; and it is a common 

 thing for a stranger, when asked to look at this curious 

 insect, to inquire where it is, and on being told that it is 

 close under his eyes, to maintain that there is no insect 

 at all, but only a branch with green leaves. 



The larger wingless stick-insects are often eight inches 

 to a foot long. They are abundant in the Moluccas ; 

 hanging on the shrubs that line the forest-paths ; and 

 they resemble sticks so exactly, in colour, in the small 

 rugosities of the bark, in the knots and small branches, 

 imitated by the joints of the legs, which are either pressed 

 close to the body, or stuck out at random, that it is 

 absolutely impossible, by the eye alone, to distinguish the 

 real dead twigs which fall down from the trees overhead 

 from the living insects. The writer has often looked at 

 them in doubt, and has been obliged to use the sense of 



