These are insects with the thighs of the hind legs swollen or enlarged, much longer than the fore legs, and adapted for jumping. The tarsi are composed of three distinct segments. The antennae are short, containing less than 30 joints; the ovipositor of the females is not sabre-shaped, but composed of short plates adapted for boring into the ground; and the organs representing ears are placed on the sides of the first abdominal segment. This group of the Orthoptera may be described as the short-horned locusts or grasshoppers in contradistinction to the tree or grass dwelling green grasshoppers with long thread-like antennae. All the true plague locusts that ravage many of the warmer countries and do an immense amount of damage belong to this division. Many species have a wide range; our locusts are allied to the African and Indian forms. Most of the species are winged, and many are capable of long sustained flight; these are furnished with air sacs in the interior of the thorax and abdomen; these when distended with air assist in lightening the otherwise heavy body. The remarkable shrill notes produced by some of these insects are caused by rubbing the inner edge of the hind thigh against the outer surface of the wing covers which are frequently furnished with ridges or raised veins for this purpose. The so-called ears consist of a membrane covering a small opening on the abdomen, and are of a somewhat different structure in different groups. [Illustration: =Fig. 22.=--Diagram of Grasshopper. _Cyrtacanthacris exacta_ (♀) (Walker). _ant_, antennae; _e_, eye; _vert_, vertex; _oc_, ocellus; _fast_, fastigium; _c. fac_, costae facialis; _c_, clypeus; _m_, mandible; _l_, labrum; _mp_, maxilliary palpi; _lp_, labial palpi; _ps_, prosternal spine; _p_, pronotum; _m. epis_, meso-episternum; _m. epim_, meso-epimeron; _co_, coxa; _tr_, trochanter; _meta-epis_, meta-episternum; _meta-epim_, meta-epimeron; _fem_, femur; _tib_, tibia; _tar_, tarsus; _sp_, spiracle; _v_, ventral valves of ovipositor. (Original W. B. Gurney.)] The reproductive organs of the female consist of several anal plates that are used after the manner of an auger to cut a circular pit in the hard soil, the abdominal segments being extended while the operation is going on; the eggs are deposited at the bottom of the hole, enclosed in a similar exudation as that which encloses the eggs of the mantis, and some of the plague locusts deposit two or more egg masses before they die. These grasshoppers have been studied by many entomologists, who have subdivided them into different groups. Brunner von Wattenwyl places them under nine sub-families or tribes chiefly based on the structure of the head. Saussure has described some of our species; Walker, Stoll and Blanchard others. [Illustration: =Fig. 23.=--_Locusta danica_ (Linn.) The Yellow-winged Locust. (“Agricultural Gazette,” N.S.W.)]