LETTERS ON ENTOMOLOGY. 117 
the lower or concave surface of the base of the 
right hand, which is uppermost, will commu- 
nicate vibrations to the areas of membrane more 
or less intense in proportion to the rapidity of 
friction. Nothing can be more annoying than the 
continual chirping of the house-cricket, which, 
however, can be silenced in general, I believe, 
by a still greater noise. Ledelius relates, that a 
woman who had tried in vain every method to 
banish them from her house, at last got rid of 
them by the noise of drums and trumpets which 
she had procured to entertain her guests *at a 
wedding. * They instantly forsook the house, 
and did not return. 
In locusta viridissima, our green English 
locust, which is very common, there is in that 
part of the right elytrum which is folded over 
the trunk, a round plate made of very fine trans- 
parent membrane, resembling a little mirror or 
piece of talc, of the tension of a drum. This 
membrane is surrounded with a very strong and 
prominent nervure, and is concealed under the 
fold of the left elytrum, which has also several 
prominent nervures answering to the margin of 
this membrane. De Geer further remarks, that 
there is every reason to believe that the brisk 
movement with which the grasshopper rubs its 
