384 THE INFLUENCE OF LIVING SURROUNDINGS. 



the water, would certainly catch but a very few individuals 

 with a glass vessel, for only under the most favourable circum- 

 stances would they bs visible to him. A resemblance of colour 

 to that of various parts .of plants is in many cases increased in 

 efficacy by the habit many creatures have of squatting close 

 and motionless when they are pursued, so that their resemblance 

 to a leaf or branch is greatly increased. The caterpillars of 

 several species of butterflies are familiar to every one, as well 

 as the ' dry leaf insect ' (see fig. 102) ; this belongs to the class of 

 leaf-eating grasshoppers, to which also belong the Phasmidse, 

 walking-stick insects (see fig. 32). They are perfectly harm- 

 less, and their resemblance to the objects which surround 

 them is evidently only a means of escape from their pursuer. 

 It is quite otherwise among the predatory Mantidse, the best 

 known of which is the ' praying mantis ' (Mantis religiosa). In 

 the accompanying cut I have represented a species of the genus 

 Acanthops which has an extraordinary resemblance to dry 

 leaves, but in this case the resemblance must be available in 

 facilitating attack. Thus the same character may conduce to 

 two different ends, attack or defence. 



Besides the cases of protective resemblance in form and 

 colour, which I have here briefly indicated, there are others 

 which we might feel disposed to regard as the exaggeration of 

 such a means of protection. In all the instances here mentioned 

 the character of the form and colouring serves for purposes of 

 concealment, irrespective of whether the ultimate end is offen- 

 sive or defensive. But in many instances of brilliant and 

 conspicuous colouring the case is quite otherwise, particularly 

 among insects ; their colours are so splendid, and the markings 

 on the wings or body so striking, that they must inevitably 

 attract the gaze of every insectivorous creature. Thus they 

 would seem to be actually forced on the attention of their ene- 

 mies, and it is probable that, not one of these vividly painted 

 forms could long escape annihilation if they had not some other 

 means of protection ; but thin, in fact, seems to be invariably 

 the case, as we learn from Wallace's admirable and exhaustive 

 researches into this subject. Thus the gaudily striped bees and 

 wisps have a sting connected with a poison-gland other insects, 



