The thorax or trunk consists really of three rings.  To the first is attached the two front legs; to the second, the two middle legs and the first pair of wings, and to the third, the two hind legs and the second pair of posterior wings.  Along the posterior margin is a well marked serrated (spinous) arrangement by means of which the locust adheres and grips forcibly.  The trunk appears to be full of a fatty sort of substance.

The abdomen consists of a number of horny segments which are joined together by an elastic membrane, a construction which enables the insect to extend its body several centimetres beyond its normal extent.  It can also be increased in thickness.

The front and middle feet of this insect are short and weak, but the length, strength, and formation of the hind legs enable it to take extraordinary leaps.  A full-grown locust can jump seven or eight feet in height, whilst it is said to be able to leap more than 200 times the length of its body.

The female is normally larger by 1/4 or 1/2 inch in length than the male, and has a rather thicker body.

The average length of the migratory locust is from 2-1/2 to 3 inches and about 3/8 inch in thickness in the abdomen.  Locusts generally lay their eggs in the spring, and the manner in which the females, having selected a favourable site, make an excavation in the earth for depositing their eggs is intensely interesting and wonderful.

At the very extremity of the abdomen the female has two pairs of horny valves or hooks, each pair placed back to back with their points directed outwards, and arranged so that all four hooks can be brought with their points close together.  By this means a sharp pointed lever is formed which can be turned around, evolved, and forked.  With this apparatus she drills a small hole and by means of a series of muscular efforts and the continuing opening and closing of the valves provided with the formation of the abdomen, she actually bores to a depth of 6 to 7 centimetres, or about 3 inches.  Here she deposits her eggs—­normally about eighty—­regularly arranged in a long cylindrical mass and envelopes them in a spumous or sort of glutinous secretion, so that the whole are quite tapped up and level with the surface of the ground.  This substance when dried is more or less impassable and affords protection to the eggs from the elements and secures an easy outlet to the surface for the young locust when hatched.  The eggs resemble in shape grains of small rice and are about 1/4 inch long.

The eggs hatch in from twenty-five to sixty days, usually about forty days, but the period may vary a little according to temperature, humidity, etc.  The young locusts are known as “hoppers,” in which stage they pass some forty-five or fifty days before arriving at the fully developed stage known as “fliers.”  To reach the “flying” or “migratory” stage they pass through six different states, changing the colour of their skin several times, gradually approaching to full growth, and finally growing wings.