138 Timehri. 



Our God-horses and Leaf-insects exhibit this character well. The 

 Mantid Stagmetoptera precaria L. and the Leaf-insect Pterochroza 

 ocellata L. (fig. 1) are particularly good examples, and one can 

 immediately see how well they would merge into their surroundings and 

 how easy it would be to overlook them. 



Among our butterflies the Agrias possess this character and will 

 serve as good examples. The upper surface of their wings are brightly 

 coloured and very conspicuous, but the undersides are dull and in general 

 appearance resemble a dry leaf. 



Those grotesque insects the Membracids are, as a whole, well pro- 

 tected for they usually resemble thorns in shape, and when perched upon 

 a branch, particularly if it bears thorns, they are fairly hard to detect. 



It must not be supposed, however, that protective resemblances need 

 necessarily always be inconspicuous, but certainly under favourable 

 conditions it is so. Our common bright sulphur-yellow butterfly, 

 Callidryas eubule L., one of the most conspicuous insects under certain 

 conditions, becomes very difficult to detect when mingled with falling 

 leaves or when it alights on a plant some of the leaves of which are 

 yellow or approaching that stage. Among the flowers of Cassia it is 

 indistinguishable until it flies off'. 



One of the most remarkable forms of protective resemblance is the 

 imitation of unpleasant objects by certain insects. The larvae of the 

 butterfly Papilio anchisiades L. which feed on citrus plants, may be 

 taken as our local example. These larvae are a dark brownish colour 

 with irregular patches of white and in general appearance resemble a 

 patch of bird-lime. When a number of these larvae are at rest in a bunch, 

 for they are gregarious, on the trunk of a lime tree they are more like 

 bits of lichen. These larvae have a further means of protection in the form 

 of an organ, known as an osmaterium, situated behind their heads, which 

 they are capable of extending and which possesses an offensive odour. 



Flash Colours. — Among all animals there are certain colours that 

 even with the greatest stretch of imagination cannot be placed among 

 ' protective resemblances.' In fact these colours are particularly con- 

 spicuous, and are constantly exhibited by the animals which bear 

 them. There is a great diversity of opinion concerning the use of such 

 colours, and we will use here the term ' flash colours.' In spite of their 

 conspicuousness these colours play a very important part in animal 

 camouflage. 



The first example we will consider here is the beautiful metallic-blue 

 butterfly Morpho menelaus L. This insect when in flight exhibits its 

 marvellous colouring with every movement of its wings and its passage 

 can easily be followed in the semi-dark forest. But suddenly it dis- 

 appears and we are completely baffled. The insect has merely closed its 

 wings and come to rest on the trunk of some tree, and we almost run our 



