a Mantis of the kind called "floral simulators." 177 



thorax unusually largely developed ; the size of the Insect being 

 much greater than that of its allies. 



(2) The colour of the front coxae, the second point of the 

 special modification, is very striking. It is remarkable even in the 

 dead specimen and has a very floral appearance during life. This 

 special coloration is, like that of the petals of certain flowers, 

 almost confined to one surface. The upper surface of the Insect 

 is altogether more pallid than the under surface. 



The attitude assumed by Idolum is very unusual. In Mantidae 

 generally the normal position of the front legs is that the coxae 

 are held together so that their inner faces are not, or are but little, 

 displayed. Idolum extends the front legs to an unusual extent, 

 and thus fully displays what is really the inner face of the coxa. It is 

 this face that bears the petaloid coloration. If Idolum held the 

 legs in the normal position the floral colour would not be seen 

 because the two coloured surfaces would be pressed together. 



In short, the attitude assumed by the Insect is thoroughly 

 correlated with the special modification of colour and structure 1 . 



Comparison of Idolum with some other Mantidae. The 

 flap-like dilatations of the front coxae are analogous to similar 

 structures found on the other coxae as already remarked, and 

 they are moreover similar to the lobes of Empusides and other 

 Mantids concerning which de Saussure has made the following 

 remarks : " The presence or absence of lobes on the abdomen may 

 appear a rather unimportant {artificiel) character. But an atten- 

 tive study indicates that in this family it is in direct relation with 

 more important modifications. In fact, in those species where it 

 is strongly pronounced all the parts of the body have a tendency 

 to assume a lacerated appearance, often very striking. The elytra 

 assume unusual forms (Gongylus); they are sometimes decoupes 

 (Acanthops) or pointed and veined like leaves (Deroplatys); the 

 prothorax also is often dilated in a leaf-like manner, and the whole 

 Insect then has a singular form that recalls the appearance of 

 vegetable objects, and renders they Insects eminently mimetic. 

 These external modifications are naturally one with (solidaires) the 

 nature of the life of the Insects exhibiting them, and hence they 

 postulate certain internal modifications of which they are only the 

 visible expression 2 ." 



1 I may add that this attitude is possibly facilitated by some small external or 

 internal modification of structure that I am not able to detect. The insect when 

 sent to me by Mr Muir was not in the position I now exhibit it in, and which it 

 will be noticed is exactly that of Mr Muir's figure. When I received it the front 

 legs were drawn together and contracted in the usual Mantid fashion. On softening 

 it with water so as to facilitate an examination of its legs, I found that the position 

 of extension they assumed on stretching was that shown in the drawing. In 

 Mantis religiosa the legs can be brought into a corresponding position and retained 

 there, only by aid of considerable pressure. 



2 Mem. Soc. Phys. Geneve, xxi., 1871, p. 2. 



