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.
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.
Fig. 67.—Blaberus Giganteus.
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.