178 Mr Sharp, Modification and attitude of Idolum diabolicum, 



Whether de Saussure's view as to this probable correlation 

 of the flap-like projections with internal conditions of which we 

 as yet know nothing prove to be correct or not, it is clear that the 

 special development of the coxae in Idolum, is merely another 

 example of a feature that is common in Mantises. 



The same conclusion is true as to the petaloid coloration of the 

 front coxae. In various Mantises, having the front limb of the 

 shape usual in the family, there is a remarkable coloration of the 

 coxa. It is well seen in the common Mantis religiosa of Europe 

 where it occurs in the same position on the limb as the petaloid 

 colour of Idolum. It is found in various degrees of development 

 according to genus and species, and in some cases is variable in 

 the individuals of the same species found in the same locality. 

 This is the case with M. religiosa, where there is always a large 

 dark mark on the inner face of the basal part of the coxa, and in 

 some individuals this mark takes the further development of be- 

 coming ocellated, the dark colour surrounding a space of a clear 

 yellow colour. 



It is unusual for the coxa to have a rose-like or purple colora- 

 tion ; but in various Mantids a colour very similar to that of the 

 petaloid coxa of Idolum is seen on other parts of the body. This 

 is the case with the posterior wings of a Rhombodera from Borneo ; 

 and in a remarkably pallid Mantis of a new genus brought by 

 Mr Graham Kerr from Paraguay this colour is found on the small 

 elytra, though there is no trace of it on any other part of the 

 body. The petaloid coloration is in Idolum confined to the front 

 coxae, while in Mr Graham Kerr's genus it is even more definitely 

 limited and confined to the elytra. 



In a small Mantid of the genus Paroxypilus from Sydney the 

 front coxae are unusually small, but they are in larger part red in 

 colour, in striking contrast to the rest of the body and to the 

 other parts of the front leg, which are of a metallic black tint. 



In none of these cases have we any reason for believing that 

 the peculiar and limited coloration is of any direct bionomic im- 

 portance to the creatures possessing it. 



This comparative review leads to the conclusion that both the 

 peculiar coloration and structure of the front coxae of Idolum may 

 be secondary or correlative characters. 



If we extend our comparison to the attitudes of the known 

 cases of floral simulators we note some remarkable facts. The 

 following interesting account of the simulation of a flower by the 

 European Empusa egena, by Krauss and Vosseler, has recently 

 been published: "The mimicry this creature carries on is surprising. 

 The second example, found at Saida, sat on a stone about the 

 size of one's hand and imitated so deceptively a greenish-white 

 anemone ( Windenbluthe) coloured at the edges and bottom with 



