136 A NATURALIST IN BORNEO 



present pressure threatening to crush organisms out 

 of existence. 



The culminating point in floral simulation by Mantidce 

 is reached in Idolum diabolicum from East Africa. 1 

 In this species, which is protectively coloured on 

 the upper-side, the prothorax is enormously expanded 

 into a plate-like disc, and the front pair of coxae are 

 also flattened and dilated ; the prothorax on the under- 

 side is white with a greenish band along its hind- 

 border, the coxae are purple throughout the greater 

 part of their length, but pinkish-white at the apex. 

 The creature rests like Gongylus back downwards 

 on shrubs, waiting for its prey, but unlike Gongylus 

 the raptorial legs are kept widely stretched out. It 

 catches its prey not by snatching at it, as other Mantidce 

 do, but by snapping the tibiae down on the femora. 

 The prothorax and front legs on their under surfaces 

 present the appearance of some remarkable exotic 

 blossom, and it is so attractive to flower-haunting 

 insects that they hover over the Mantis or actually 

 settle on it. Here there is no trace of warning color- 

 ation ; all the parts which in other species are coloured 

 with the object of scaring enemies are so coloured 

 as to resemble the petals of a flower, and, so far as is 

 known, the insect does not adopt any threatening 

 attitude when irritated. We may, perhaps, safely 

 assume that while its floral simulation attracts its prey, 

 the same adaptation as well as to its protective colour- 

 ing on the upper surface enables it to elude the 

 observation of its enemies. Idolum is, moreover, a 

 large, robust insect, with very heavily armed raptorial 



1 Sharp, Proc. Cambridge Phil. Soc., X. (1898-1900), pp. 175-80, 

 PI. II. 



