of a Stridu.lutliKj Apparatus in certain Maiitidce. 267 



examination of some of those species might furnish at 

 least a clue, I have accordingly examined the tegmina of 

 H. vitrea and of several other species, and I hnd that 

 the fore margin of those organs, though smooth and entire 

 to the naked eye, appears under a lens or under a low 

 power to be minutely and irregularly serrated or jagged; 

 the teeth, which are very variable in number, arrange- 

 ment, and size, benig sometimes microscopically small, are 

 all directed outwards and slightly forwards towards the 

 extremity of the organ, just as in the more distinct and 

 regular serratures of the same part in many Dragon-flies, 

 but instead of being rough and sharp, as in these, they 

 are smooth and blunt, often even more or less bulbously 

 enlarged at the extremity, where each is furnished with a 

 minute brown seta, which is also directed towards the 

 point of the wing. In the Indian Hierodula coarctata, 

 the teeth are more highly developed and their points 

 extend distinctly beyond the setas, which project straight 

 outwards from their apical side. There is little doubt 

 that the teeth in this species serve to some extent for the 

 production of sound. On reference to my drawing (fig. 2) 

 of a portion of the tegminal edge of the African H. c/as- 

 trica, in which the apparatus is more highly developed 

 than in any other species of the genus, it will be seen 

 that each of the teeth is in that species also furnished in 

 identically the same position with a similar seta ; and the 

 Australian Hierodula dentifrons is so far intermediate 

 between these two that it is rather less modified as to its 

 tegmina than the latter. 



Similar setee are also present in all the Empusidce* in 

 which they are inserted immediately at the base of the 

 hard, polished, and brown-coloured terminal tubercle. 

 They cannot form an essential part of the apparatus ; 

 but they are of importance as clearly showing that the 

 teeth of the rasps are morphologically identical with the 

 microscopically small blunt serratures seen in such a form 

 as the Malayan Hierodula vitrea, and must consequently 

 have originated from similar small and variable beginnings. 



* In several evidently old specimens of IdoJomorplm cajjensls, however, 

 they are absent from the teeth of what I consider to be the functional part 

 of the rasp, having apparently been rubbed off by the action of the scraper. 



