(453 ) at ors 
V. Observations on the Crepitaculum and the Foramina in the 
anterior Tibia of some Orthopterous Insects. By the Rev. Lans- 
down Guilding, D.A. F.L.S. 
Read June 7, 1825. 
_ Or the organs possessed by the insect tribes, none merit dili- . 
gent examination more than those which are connected with the 
production of sound. The structure of most of them is well 
known at the present day, and has been elucidated by accurate 
figures. Some, however, require further explanation. I shall 
briefly notice one insect, and describe its crepitaculum, and the 
tibial foramina of two orthopterous genera *. x 
The subdiaphanous horny apparatus at the base of the wings 
of the male Locustæ and Achetæ has long since been observed to 
be the instrumentum stridoris by which the mute female is invited 
by the male to celebrate their nuptials; but the peculiar and 
admirable structure of the part has not been shown in a satis- 
factory manner by the engraver. In different species it varies 
greatly, but in the one I shall notice it is exceedingly complete. 
On the horny base of the left hemelytron, beneath, a strong ridge _ 
projects, which is furnished with hard and regular teeth : on the 
right one, a bony process is placed, so as to act on the serrated 
* Drawings of the several parts, by the author, are deposited in the collection of . 
the Society. 
FOU. XV. < x projection 
