ENTOMOLOGY. 307 



Gehororgan der Orthopteren. (Wiegm. Archiv. 1844, vol. i, 

 p. 52.) 



The drum-shaped organ above the hind legs in the A.cridii,* the apertures, 

 closed with a tight membrane, in the fore-shanks of the Locustaef and Acheta?, 

 are the parts wliich the author thinks he is enabled to designate as the 

 organ of hearing, on the ground of anatomical relations. It is not to be 

 gainsaid that these organs possess every recmisite to be the seat of the 

 sense under consideration. But the question may fairly be put, where is 

 the corresponding organ in other insects. In all other animals the organ of 

 hearing is in immediate connexion with the brain (vertebrata), or with the 

 loop which embraces the throat (invertebrata). The same objection I 

 have before advanced in answer to Goureau, who, reasoning a priori, had 

 come to an opinion like that of Siebold. (Report 1837, p. 198.) 



Westring (Kroyer Nat. Tidsskr. N. Rakk. i, 58) has 

 detailed his researches concerning the instruments of sound 

 in insects, from which the general inference is drawn, that 

 in every case where a sound is produced by the friction of 

 two separate parts, the surfaces in contact are wrinkled or 

 shagreened, or else a prominent edge of one plays against 

 the wrinkled or fluted surface of the other. 



1. Geotrupes stercorarius, sylvaticus, vernalis, have at the back side of the 

 last pair of hips a corner fluted crosswise, against which the sharp hinder 

 rim of the second abdominal segment plays. The moving instrument is 

 here the abdomen, and the hip the fixed one. 



2. Copris lunaris lias a slightly raised ledge on the fore rim of the 

 breech-plate (pygidium), and on the underside of the shards (elytra), near 

 the seam and extending to nearly a fourth of its length, a ridge scored 

 crosswise, against wliich the ledge plays when the breech-plate is put in 

 motion. 



3. The Cerambycidfe and Lepturidfe, as is known, rub the hind rim of the 

 fore-chest (prothorax) against the neck of the mid-chest (mesothorax), 

 which part Goureau has erroneously described as smooth ; it is in reality 

 wrinkled or fluted crosswise. 



4. In Necrophorus there are found two ridges ramming lengthwise, and 

 parallel, down the back of the fourth segment of the abdomen. These are 

 fluted crosswise or scolloped, and form the moving instrument, being rubbed 

 against a project ing cross-ledge under the end of the shards. 



5. Cychrus, Trox, Lema, Cryptorrhynchus lapathi have a ridge on the 



* Locust Ida 1 , Lch. f Gryllidee. Lch. 



