Grasshoppers, Katydids, Crickets, Etc

(Order Orthoptera.)

This is a large and important group of insects which comprises those forms which are known as the straight-winged insects and includes the grasshoppers, or true locusts, the longhorned grasshoppers (including the katydids), the crickets, cockroaches, walking sticks and leaf insects, and the praying mantids or rearhorses. In all these insects the mouth-parts are fitted for biting and the metamorphoses are incomplete, the young when hatching from the eggs resembling the adult except for the lack of wings. The eggs are comparatively few in number and are laid in specialized egg cases. The fore wings are somewhat thickened and rather tough and horny as a rule, though not so much so as the elytra of beetles and at rest lie closed on the back of the insect so as to protect it and the hind wings. They are called tegmina. The hind wings are much more delicate and are the important ones in flight. They are furnished with radiating veins somewhat like the sticks of a fan and have short cross-veins forming a sort of network. In repose they fold like a fan and are more or less covered by the fore wings. While the order is not such an extensive one in number of species, it is one of very great economic importance, largely through the ravages which the migratory locusts, or short-horned grasshoppers, make upon agricultural crops in various parts of the world and the numbers in which not only these insects but certain other forms occur, while their comparatively large size and frequently conspicuous appearance, make the group a noted one.

As to size, the Orthoptera probably include the largest of living insects and this is particularly the case in tropical countries. Even in this country, however, it is doubtful whether any insect exceeds in actual bulk the large lubber grasshoppers of our Southeastern and Southwestern States. It is estimated that probably ten thousand species of Orthoptera exist in the world, but this estimate is probably a small one, since, as in the other groups, the smaller and more inconspicuous species have not been collected in out-of-the-way places. The average traveller who picks up specimens, and even the average collector, when he goes to some rarely visited corner of the world, will always collect the large and conspicuous things and neglect the smaller and more insignificant specimens. From this habit, it results that in the large museums, like the British Museum, the Berlin Museum and the Vienna Museum, and our own National Museum, large, exotic forms from most portions of the world are well represented, but there are comparatively few of the little dull-colored ones.

The order Orthoptera affords a peculiar interest to the student of the phenomena of protective and aggressive resemblances. The family Phasmidae includes those remarkable creatures which are so much like twigs and leaves that they have been called walking sticks and leaf insects. It also includes the great group of praying mantids which feed upon other insects and which, though slow movers, are enabled to capture their prey by means of their perfect disguise which, in temperate regions, makes them resemble twigs and in tropical regions brings about an extraordinary resemblance to flowering vegetation, some of them being most highly colored, as the flower mantids, which resemble the most conspicuous orchids.

Another fact which renders this group of especial interest is that many of them are so musical. One often hears of the "song" of the katydid, but as a matter of fact, these insects are not vocalists but instrumentalists. Portions of the body are so modified as to produce musical sounds by the rubbing of one part upon another. In the crickets it is the rubbing of the upper wings upon the hind wings, the membrane being veined in such a way as to produce a chirping sound. In some of the grasshoppers the sound is brought about by the rubbing of the hind thighs against the edge of the fore-wings, or "tegmina." These musical powers are confined to the male sex and the tunes which they play are, while songs without words, always love songs.

Many of the Orthoptera are great jumpers, their hind thighs being thickened so as to enable them to make great leaps. The common name grasshopper is based upon their facility in this direction. This reminds me of the little girl, who, being told that the beetles were Coleoptera and that the butterflies were Lepidoptera, remarked that the grasshoppers must be the "Grasshoptera." Many of the Orthoptera fly well and strongly. The migratory grasshoppers frequently fly for hundreds of miles with daily rests for food, sometimes in such enormous swarms as to darken the face of the sun.