ORTHOPTERA. 89 



Gryllidae, and Locustidae, are interesting on account of the sounds 

 which they produce. A very large proportion of the insect cries 

 heard in the late summer and autumn come from this source. The 

 organs by which these notes are made are chiefly the wing-covers. 

 It should be remembered that, owing to their peculiar mode of 

 breathing, insects have nothing that corresponds to our voice. It is 

 only the males of the Orthoptera that sing ; and the musical appa- 

 ratus is different in each of the three families. Each form will be 

 described later. 



In this connection perhaps reference should be made to the sup- 

 posed organs of hearing of these insects. In the Acrididae there is 

 on each side of the first abdominal segment a pit, over the mouth of 

 which is stretched a membrane : this is termed the tympanum, and is 

 believed by some to be an organ of hearing ; it is doubtless a sense- 

 organ, but its function has not yet been determined. A pair of 

 similar organs occur near the proximal end of each tibia of the first 

 pair of legs in the Locustidae and Gryllidae. 



The order Orthoptera comprises seven families. These have 

 been grouped into five sections by some writers ; and the names of 

 the sections occur frequently in entomological works. Each of the 

 first four sections includes only a single family ; the fourth section 

 includes the three remaining families. The names of the sections 

 except the first were suggested by the form of the legs in each. 

 The following are the names of the sections and the families which 

 they include : 



I. Dermdptera ; includes the Forficiilidce or Earwigs. 

 II. Cursoria or Runners ; includes the Bldttid<z or Cockroaches. 



III. Raptoria or Graspers; includes the Mdntidce or Rear-horses. 



IV. Ambulatoria or Walkers; includes the Phdsmida or Walking- 

 sticks. 



V. Saltatoria or Jumpers ; includes the Acrldidce or Locusts or 

 Short-horned Grasshoppers, the Locustidce or Long horned Grass 

 hoppers and Katydids, and the Gryllidce or Crickets. 



TABLE OF FAMILIES OF ORTHOPTERA. 



A. Posterior femora fitted for walking, i.e., resembling those of the other legs ; 

 ovipositor with the subgenital plate concealed ; organs of flight of immature 

 forms in normal position ; insects mute. 



B. Anterior wings leathery, very short, without veins, meeting in a straight 

 line; posterior wings when present folded to the middle of the anterior 



