IMPERFECT SOCIETIES OF INSECTS. 15 



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 uniformly 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 hundred 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 : their way can only be im- 

 peded by the waters of brooks or canals, as they are ap- 

 parently terrified at every kind of moisture. Often, how- 

 ever, they endeavour 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 sun- 

 set 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 a ." 



" In the month of May, when the ovaries of these in- 

 sects were ripe and turgid," says Dr. Shaw 5 , "each 

 of thes swarms began gradually to disappear, and re- 



3 Pallas, ii. 422-6. b Travels, 187- 



