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 

 beetlS^ dfte of' 



Fig. 100. — Stridulating organ of an arit, Myrmica rubra 

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



the two parts of the stridulating organ ig situated upon 'the elytra;' 

 and it is quite probable that in these cases the'felytra acts as vibratitt^i'' 

 surfaces, as do the wings of locusts and ci'ickets. But in rriany 

 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. IcBvinodis, 

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

 one abdominal segment, and the file is situated on the dorsvim of 

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



