The species of Acridiidae that have been ascertained to be migratory are not numerous.[230] The most abundant and widely distributed of them is _Pachytylus cinerascens_ (Fig. 177), which has invaded a large part of the Eastern hemisphere, extending from the Atlantic Ocean to China. It exists in numerous spots in the Oriental region and the Asiatic Archipelago, and even in New Zealand. It is the commoner of the locusts of Europe. Its congener, _P. migratorius_, is much less widely distributed, its migrations being, according to de Saussure, limited to Turkestan and Eastern Europe. A third species, _P. migratorioides_, inhabits Eastern Africa, and a variety of it is the "Yolala" or locust of Madagascar. Mr. Distant has informed the writer that this migratory locust is found in South Africa. _P._ (_Oedaleus_) _marmoratus_ has almost as wide a distribution in the Eastern hemisphere as _P. cinerascens_, except that it is more exclusively tropical; it is thus excluded from New Zealand. _P._ (_Oedaleus_) _nigrofasciatus_ has a more northern distribution than its congener, but has extended to Africa and the Asiatic Archipelago. This Insect is so variable that the distinctions of its races from other species of the same genus are not yet clear. All the above-mentioned locusts belong to the tribe Oedipodides. _Acridium peregrinum_, now more frequently called _Schistocerca peregrina_, belongs to the tribe Acridiides. It is a large locust (Fig. 84), and has a wide distribution. It is the chief species in North Africa, and is probably the locust of the plagues of Egypt mentioned in the book of Exodus. It is also, according to Cotes,[231] the chief locust of North-West India. In this latter country _Pachytylus cinerascens_ and some other species also occur. With the exception of _S. peregrina_, the species of the genus _Schistocerca_ are confined to the New World. In North America locusts are more usually called grasshoppers. Several species of the genus _Caloptenus_ are injurious in that country, but the chief migratory species is _C. spretus_ (Fig. 175). This genus belongs to Acridiides. A large locust, _Schistocerca americana_, is also migratory to a small extent in the United States. In South America other species of _Schistocerca_ are migratory; it is not known how many there may be, and it is possible that one or more may prove to be the _S. peregrina_ of the Old World. A Chilian species, according to Mr. E. C. Reed,[232] {299}exhibits distinctions of colour similar to those that have been observed in _S. peregrina_ in Algeria. [Illustration: FIG. 178.—_Cephalocoema lineata_, female, × ⅔. S. America. (After Brunner.)]