THE EXTERNAL ANATOMY OF INSECTS 



87 



Rasping organs of other than orthopterous insects. Rasping 

 organs are found in many other than orthopterous insects and vary 



M 



Fig- 99- Right fore wing of an adult male of Conocephalus, seen 

 from below; /, file; s, scraper. 



greatly in form and in their location on the body. Lack of space for- 

 bids any attempt to enumerate these variations here ; but examples of 

 various types of stridulating organs will be described in later chapters 

 when treating of the insects that possess them. As in the Orthoptera, 

 they consist of a rasp and a scraper. The rasp is a file-like area of the 

 surface of a segment of the body or of an appendage; and the scraper 

 is a hard ridge or point so situated that it can be drawn across the rasp 



by movements 

 of the body or 

 of an append- 

 age. In some 

 cases the ap- 

 paratus con- 

 sists of two 

 rasps so situ- 

 ated that they 

 can be rubbed 

 together. 



With many 

 beetles one of 



Fig. 100. Stridulating organ of an ant, Myrmica rubra 

 -(From Sharp after Janet); d, scraper; e, file. 



the two parts of the stridulating organ is situated upon the elytra ; 

 and it is quite probable that in these cases the elytra acts as vibrating 

 surfaces, as do the wings of locusts and crickets. But in many 

 cases as where a part of a leg is rubbed against a portion of a 

 thoracic segment, there appears to be no vibrating surface unless it is 

 the wall of the body or of the appendage that acts as a sounding 

 board. In the stridulating organ of Myrmica rubra, var. Icevinodis, 

 figured by Janet (Fig. 100), the scraper is the posterior border of 

 one abdominal segment, and the -file is situated on the dor sum of 

 the following segment. It is quite conceivable that in this case 



