Insect Camouflage. 137 



question arises " What is the use of these colour patterns ? " In answer- 

 ing this question it is necessary to find a real usefulness for this colour- 

 pattern, a usefulness to the colour-bearing animals themselves, — a useful- 

 ness of sufficient importance to account for a so highly specialized 

 development. 



Perhaps we can find the explanation in " camouflage." 



Although the majority of insects which we observe are brightly 

 coloured, one has only to go through any field or pasture and notice the 

 number of insects that are disturbed, — insects that were not noticeable, 

 not because they were hidden but because they were inconspicuous. 



The most common means of camouflage amongst insects, and the one 

 most generally employed by man, is the imitation of their surroundings. 



Protective Resemblance is probably the most primitive form of 

 defence practised by insects, and as it is at present the form usually 

 adopted, we may presume it is the most successful. Protective resem- 

 blances may be grouped into two classes — 1, General Protective Resem- 

 blances, and 2, Special Protective Resemblances. 



Under the first group we get insects such as green grasshoppers. 

 Here the general coloration is protective to the insect when it hides 

 amongst the leaves of trees. There are many moths that when at rest 

 with their wings closed resemble the trunks of trees against which they 

 are usually found. Some good examples can be found in the family 

 Sphingidse or Hawk Moths, and the Frangipanni Sphinx, Pseudospkinx 

 t.elrio L., and the Cassava Hawk Moth, Errytiis ello L., both exhibit such 

 coloration. The adults of the Small Moth Borers, Diatrcea saccharalis F., 

 D. canella Hmps., and D. hneola Walk., are all well protected in this 

 way for when at rest their colours blend almost exactly with the trash of 

 canes or dry blades of grass. 



Another example of the same kind of resemblance, but in this 

 instance in a butterfly, is the White-skirted Calico butterfly, Ageronia 

 feronia L. It is usual for butterflies to close their wings when they 

 alight, but this particular insect comes to rest with its wings wide open 

 against the trunk of a tree, and its head pointing downwards. In such 

 a position this insect is well protected for it is the upper surface of the 

 wings that is protectively coloured and blends beautifully with the bark. 



Still another example, but in an entirely different order, is the bug 

 ( Pentatomidae) Phloea corticata F. This insect when resting against 

 the bark of a tree, the position where it is usually found, resembles its 

 surroundings so well that it could easily be overlooked. 



Among other insects such as Mantids, — God-horses as they are 

 called locally, — Leaf-insects and certain butterflies the resemblance is 

 carried further and the shape and pattern, as well as the general colour 

 of their surroundings is accurately copied. 



