92 
ORTHOPTERA. 
tinct from Gryllids in the wings and tarsi. These insects are usually of 
large size, none of less than half an inch in length, a few exceeding two 
inches. They are less robustly built than the Acridiids and include a 
greater variety of forms. Many are elongate, the body narrow, the 
general colour green variegated with darker tints, their form and colour 
blending with the grass or vegetation among which they live. Others 
are larger, the tegmina broader and leaf-like; (fig. 31) the colour is green 
Fig. 31 -Holochlora albida. 
and the veins of the tegmina suggest the veins on a green leaf. These 
live upon bushy plants and are well concealed. Others living upon bark 
are grey, the tegmina roughened, and so closely adapted are they to their 
habitat that they can scarcely be seen until they are in motion. 
The antennae are very long and fine, with many joints, functioning 
as delicate organs of touch. The mouthparts are of the herbivorous 
type, the mandibles short and powerful, the palpi well developed. The 
prothorax is large and distinct; the tegmina are thickened and coloured, 
usually sloping over the abdomen, with a small basal flat area. In the 
males, this flat area is modified to form a sound producing organ ; the 
right tegmen overlaps the left and has on its lower surface a sharp point; 
the left on its upper surface a file ; by the movement of the tegmina, 
vibration is produced, the sound being intensified by the stiff tegmina. 
In some species this organ occurs in both sexes. The hind wings are large 
