IMPERFECT SOCIETIES OF INSECTS. 333 



that they are merely the result of a common origin and station ; but those 

 of the latter, the locusts, wear more the appearance of design, and of 

 being produced by the social principle. 



So much as the world has suffered from these animals, it is extraordinary 

 that so few observations have been made upon their history, economy, 

 and mode of proceeding. One of the best accounts seems to be that of 

 Professor Pallas, in his Travels into the Southern Provinces of the Rus- 

 sian Empire. The species to which his principal attention was paid 

 appears to have been the Locusta Italica, in its larva and pupa state. 

 "In serene warm weather," says he, "the locusts are in full motion in 

 the morning immediately after the evaporation of the dew ; and if no dew 

 has fallen, they appear as soon as the sun imparts his genial warmth. At 

 first some are seen running about like messengers among the reposing 

 swarms, which are lying partly compressed upon the ground, at the side 

 of small eminences, and partly attached to tall plants and shrubs. Shortly 

 after, the whole body begins to move forward in one direction and with 

 little deviation. They resemble a swarm of ants, all taking the same 

 course, at small distances, but without touching each other : they uni- 

 formly travel towards a certain region as fast as a fly can run, and without 

 leaping, unless pursued ; in which case, indeed, they disperse, but soon 

 collect again and follow their former route. In this manner they advance 

 from morning to evening without halting, frequently at the rate of a hun- 

 dred fathoms and upwards in the course of a day. Although they prefer 

 marching along high roads, footpaths, or open tracts, yet when their 

 progress is opposed by bushes, hedges, and ditches, they penetrate through 

 them : tlieir way can only be impeded by the waters of brooks or canals, 

 as they are apparently terrified at every kind of moisture. Often, however, 

 they endeavor to gain the opposite bank with the aid of overhanging 

 boughs ; and if the stalks of plants or shrubs be laid across the water, 

 they pass in close columns over these temporary bridges, on which they 

 even seem to rest and enjoy the refreshing coolness. Towards sunset the 

 whole swarm gradually collect in parties, and creep up the plants, or 

 encamp on slight eminences. On cold, cloudy, or rainy days they do not 

 travel. As soon as they acquire wings they progressively disperse, but 

 still fly about in large swarms."^ 



" In the month of May, when the ovaries of these insects were ripe 

 and turgid," says Dr. Shaw^, " each of these swarms began gradually to 

 disappear, and retired into the Mettijiah, and other adjacent plains, where 

 they deposited their eggs. These were no sooner hatched in June, than 

 each of the broods collected itself into a compact body, of a furlong or 

 more in square, and marching afterwards directly forwards toward the sea, 

 they let nothing escape them — they Icept their ranks like men of war ; 

 climbing over, as they advanced, every tree or wall that was in their way ; 

 nay, they entered into our very houses and bed-chambers, like so many 

 thieves. A day or two after one of these hordes was in motion, others 

 were already hatched to march and glean after them. Having lived near 

 a month in this manner, they arrived at their full growth, and threw off 

 their nympha-state by casting their outward skin. To prepare themselves 

 for this change, they clung by their hinder feet to some bush, twig, or 



» Pallas, ii. 422—426. 2 Travels, 187. 



