The _Euplexoptera_, or Earwigs, are regarded by some authors as a separate order. They are thus treated by Westwood in his "Introduction to the Modern Classification of Insects," but the modern tendency is to revert to the Linnæan system, and retain them among the _Orthoptera_. [Illustration: Fig. 65.--Phasgonura Viridissima.] TABULAR VIEW OF THE PRINCIPAL FAMILIES OF THE ORTHOPTERA. TRIBE I.--CURSORIA. Family 1. Blattidæ or Cockroaches. Family 2. Mantidæ or Praying Insects. Family 3. Phasmidæ or Stick and Leaf Insects. TRIBE II.--SALTATORIA. Family 4. Achetidæ or Crickets. Family 5. Gryllidæ or False Locusts. Family 6. Locustidæ or True Locusts and Grasshoppers. TRIBE III.--EUPLEXOPTERA. Family 7. Forficulidæ or Earwigs. We will now proceed to describe each of these families in turn. TRIBE I.--CURSORIA. The insects constituting this group are distinguished by having their hind legs adapted for walking or running. They are subdivided into three families. _Family 1, Blattidæ._--This family includes the numerous species of cockroaches, or "black bats" as they are often called by uneducated persons. They are represented in all parts of the world, but are most abundant within the tropics, and especially in central and southern America, where also the largest and finest species are to be found. Many curious forms are also to be met with in India and different parts of Africa. They are very active creatures, and run with considerable rapidity, but their activity is chiefly nocturnal, and during the day they generally remain quietly concealed in some obscure retreat. Their diet consists of both vegetable and animal matter, and offal of every description. They are most useful in hot climates, acting the part of scavengers, and by these means preventing the outbreak of malaria and other pestilential diseases. The best-known species in this country is the common Cockroach (_Blatta orientalis_), which, by-the-bye, is not a native of Europe, having been introduced from the East several centuries ago, and to have made its home here. [Illustration: Fig. 66.--Blatta Orientalis.] Other species besides this are met with occasionally in different parts of the country, having been introduced in like manner at different times from foreign parts. The Giant Cockroach (_Blaberus giganteus_) is one of these. Its native home is South America and the West Indies, and in the latter place it is commonly called the "drummer." It measures nearly three inches in length. The Zoological Gardens in London is a favourite resort of this species. [Illustration: Fig. 67.--Blaberus Giganteus.] [Illustration: Fig. 68.--Corydia Petiveriana.] _Family 2, Mantidæ._--The _Mantidæ_ may be at once distinguished from the insects comprising the other two families of the _Cursoria_ by the structure of the forelegs, which are converted into powerful raptoral organs.