LOCUST ( from Lat. locusts, locust, lobst Any orthopterous insect of the family Aeridiid:c. Much confusion has arisen in the use of this term, for two reasons: The family Locustithe, including the typical genus Locusta, are popu larly termed `long-horned grasshoppers'; and, on the other hand. 'locust' is given popularly (in the Orthoptera) only to members of the Acridii Nvhich are also termed 'short-horned grass hoppers.' (See GnAssnoecEu.) In the United States a further confusion arises from the fact that the term 'locust' is applied to any member of the hemipterous family Cicadidoc, which includes the so-called seventeen-year 'locust' or periodical cicada (see CicAnA. and IIENtievEnA) and the com mon dog-day harvest-tly. The name, however, should lie restricted to the insects of the family Acridiid:e, and is so used by all English speak ing people except in portions of the United States.
Locusts may be distinguished from the long horned grasshoppers and the crickets, such as the common .taabras sirn plc.r, by the relatively short antenme, the short ovipositor of the female, and the long, hind legs with thickened thighs. They stridulate by the of the rough hind legs against the wing-covers, this method differing from the stridulation of the katydids and crickets (q.v.). The wing-covers are leathery and narrow, the wings themselves being broad, and \Olen at rest folded like a fan.
The 'mover of flight in locusts varies with the species. Those capable of sustaining, prolonged flight have large trach•al dilatations within the body. he species of greatest economic importance in the United States are the Rocky :Mountain locust (.11elanoplus Apielus), the red-legged locust ( Mein nopl s fent r-rul»-u »1) , the lesser III locust (11clanoplus !antis), the American locust ( Sehistnecrra incrira no ) and the differential locust different hulls . The Old World migratory locusts belong principally to two spe cies. Pachyt ylusz migralorims and Aeridiuin perr grimon. A South American species of the genus Aeridimn frequently inflicts great damage upon crops in Argentina and Chile. while in South Africa a migratory locust comes down from the north in swarms and destroys the crops of the settlers. These few species, possessing great powers of multiplication and extended powers of flight, have been classed among the wo•ld's his torical scourges. Early incursions in Europe and North Africa are mentioned by Ororius and Saint Augustine, the latter recording a plague in Numidia which resulted in the death of 800,000 men. Pliny states that locusts came over in great. swarms from Africa to Italy in his time. Incursions as far north as Germany occurred in 1333 lasting until 1336, 1475, 1527, 1543, 1636, 1686, and at intervals until 1856-59.
The Rocky Moinitain locust of the United States formerly bred over vast areas in the Northwest and at intervals migrated in immense swarms for hundreds of miles beyond its usual habitat. In MIS and 1819 that part of the
country now known as Minnesota was covered by vast swarms: in 1820 the western part of :Missouri was ravaged; in 1842 they again ap peared in Minnesota and Wyoming. and in 1845 in Texas and again in 1849. They appeared in Utah nearly every year from 1851 to 1877. and a portion of Utah at one time was included in the permanent breeding-grounds of this species. An unusual locust year was 1856, when the insects swarmed over Kansas and Nebraska, the western counties of Missouri and northeastern Texas. and in Iowa, Minnesota, Colorado. and Utah. in 1870 to 1871 they again began to increase, and in 1873 were very injurious. The most disastrous locust year known in the United States, however, was 1874, when enormous invaded the set tled portions of the Mississippi Valley west of the ninety-fourth meridian. Colorado, Nebraska, Kansas, Wyoming,•, Dakota, Minnesota, Iowa, Missouri, New Mexico, Indian Territory, and Texas were overrun by swarms from the North west, mainly from Montana and British America. The loss in this region was estimated at $50.000. 000 iu the actual destruction of crops. In 1375 the young insects hatched in immense numbers over an area embracing portions of Nebraska, Kansas, and Missouri, entailing destitution and suffering among a population of 750.000 people. In 1877 the young insects died in great numbers, and those which acquired wings flew toward the Northwest in the direction of Dakota and Mon tana. the region of the permanent breeding grounds.. The district in which the insect was considered to breed permanently mapped by the United States Entomological Commission in 1877. It was stated that the area comprised about 300,000 square miles. The most favorite breeding-places in this area were the river bot toms and the sunny slopes of uplands or the grassy regions among the mountains. At the same time a 'sub-permanent' breeding region in which the insects breed more or less continuously was also mapped out. When the Entomological Commission finished its labors in 1879 these con clusions were practically confirmed. Since that time. however, much of that region has been greatly changed in character by settlement and by the introduction of agriculture. The result bias been that the permanent breeding-grounds of the Rocky Mountain locust have'been greatly restricted, and in fact it has practically been driven beyond the borders of the United States, and now breeds freely only in portions of British Columbia. From those grounds, however, occa sional swarms fly south into the Northwestern States and do more or less damage for a single season, as has been the case in restricted locali ties in Minnesota and North Dakota the past few years.