ORDER ORTHOPTERA 249 



distinguished by the following combination of characters : — The antennse 

 are comparatively short, consisting of less than 30 segments ; the tarsi 

 consist of only 3 separate segments ; and in the female there is no 

 projecting ovipositor. Moreover, the auditory drums lie in the ist 

 abdominal segment, just behind and above the articulation of the 

 hind legs. The chirping of these grasshoppers is usually performed 

 by rubbing the inner surface of the hind femur — where there is a row 

 of small pegs — against the outer surface of the tegmen or front wing — 

 where there is a prominent sharp-edged vein ; and this apparatus, 

 though not confined to the male, is peculiarly well developed in that sex. 

 The name "locust" is applied to about half a dozen species of large 

 Acridiidm that, in many parts of the world, periodically swarm and 

 migrate, either in the adult form by flight, or in the earlier wingless 

 stage on foot. The female Acridiid lays her eggs in inspissated masses 

 in holes dug in the soil by the hardened end of her abdomen. 



Family Locustidoe (Lat. locusta = a locust) : Long - antenna Grass- 

 hoppers. It must be remembered that the destructive migratory 

 "locusts" do not belong to this family, the members of which though in 

 the main herbivorous are not exclusively so. In the LocustidcB the 

 antenna are extremely long and slender, consisting of many more than 

 30 segments ; the tarsi are composed of 4 distinct segments ; and 

 the female usually possesses a long, sabre-shaped ovipositor. The 

 auditory drums when present (or the chinks that lead to them) are to be 

 found in the tibiae of the front pair of legs. The trilling of these grass- 

 hoppers is made by rubbing the bases of the tegmina, or front wings, 

 together, one tegmen having a file of teeth on its inner surface, the 

 other having its inner margin sharpened to act as a scraper. It is 

 usually only the male that is musical. Dr R. Howard brought to the 

 London School of Tropical Medicine, from an island in Lake Nyassa, 

 a specimen of Enyaliopsis petersii, one of the ugly wingless species of 

 LocustidcE, stating that it has the reputation of either giving a bite or 

 exuding a fluid that causes extensive superficial inflammation and 

 vesication. 



Family Gryllidce (Lat. gryllus = a cricket) : Crickets. The species 

 of this family are dingy-coloured insects with tegmina, or anterior wings, 

 closely fitted to the back and sides of the body. The antennse are 

 generally long and slender ; the tarsi usually have 3 segments, but 

 sometimes 2 or 4 ; and the female usually possesses a long awl- 

 shaped ovipositor. The auditory drums, and the chirping mechanism 

 of the male, agree with those of the Locustidce. The anal cerci are 

 long and unsegmented, and often the tips of the wings are rolled up, and 

 project beyond the body like an additional pair of cerci. 



