HEMIPTERA. 431 



sound which has induced authors to designate them by the name of Canta- 

 trices or Singers. 



The organs by which it is effected are situated on each side of the base 

 of the abdomen; they are internal, and each one is covered by a cartilaginous 

 plate, which closes like a shutter. The cavity which encloses this appa- 

 ratus is divided into two cells by a squamous and triangular septum. When 

 viewed from the side of the abdomen, each cell presents anteriorly a white 

 and plaited membrane, 'and lower down, in the bottom, a tight, thin, trans- 

 parent membrane, which Reaumur terms " le mirior" If this part of the 

 body be opened above, another plaited membrane is seen on each side, 

 which is moved by an extremely powerful muscle composed of numerous, 

 straight, and parallel fibres, and arising from the squamous septum. This 

 membrane is the tymbal. The muscles, by rapidly contracting and relax- 

 ing, act on the tymbals, alternately tightening and restoring them to their 

 original state. Such is the origin of these sounds, which can even be pro- 

 duced after the death of the Insect, by jerking the muscle. 



The Cicadse live on trees or shrubs, of which they suck the juices. The 

 female, by means of an ovipositor enclosed in a bilaminated, semitubular 

 sheath, and composed of three narrow, elongated, squamous pieces, two of 

 which terminate in the form of a file, pierces the dead twigs to the medulla, 

 in which she deposits her eggs. As the number pf the latter is considera- 

 ble, she makes several holes, indicated externally by as many elevations. 

 The young larvae however leave their asylum to penetrate into the earth, 

 where they grow and experience their metamorphosis. Their anterior 

 legs are short, have very stout thighs armed with teeth, and are adapted for 

 digging. The Greeks ate the pupae, which they called Tettigometra, and 

 even the perfect Insect. 



The C. orniy by wounding the tree from which its specific name is de- 

 rived, produces that peculiar honey-like and purgative juice called manna. 



C. orni, L. About an inch long; yellowish; pale beneath, the same 

 colour mixed with black above; margin of the abdominal segments, russet; 

 two rows of blackish points on the elytra, those nearest their inner margin 

 the smallest. South of France, Italy, &c. 



The other Cicadariae Mutes have but three distinct joints in 

 the antennas, and two small ocelli. Their legs are usually adapted 

 for leaping. Neither of the sexes is provided with organs of sound. 



The elytra are frequently coriaceous and opaque. Several fe- 

 males envelope their eggs with a white substance resembling cotton. 



Some of them Fulgorellse have the antennae inserted immediately un- 

 der their eyes, and the front frequently prolonged in the form of a snout, 

 the figure of which varies according to the species. By this we distinguish 

 the genus 



