14 IMPERFECT SOCIETIES OF INSECTS. 



very fond of each other's company when they feed. To- 

 wards the latter end of last July, walking through a 

 wheat-field, I observed that all the blossoms of Convol- 

 vulus arvensis, though very numerous, were interiorly 

 turned quite black by the infinite number of these in- 

 sects, which were coursing about within them. 



But the most interesting insects of this order are those 

 which associate in all their states. — Two populous tribes, 

 the great devastators of the vegetable world, the one in 

 warm and the other in cold climates, to which I have 

 already alluded imder the head of emigrations — you 

 perceive I am speaking of Aphides and Locusts — are the 

 best examples of this order : although, concerning the 

 societies of the first, at present we can only say that they 

 are merely the result of a common origin and station : 

 but those of the latter, the locusts, wear more the ap- 

 pearance 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 proceed- 

 ing. One of the best accounts seems to be that of Pro- 

 fessor Pallas, in his Travels into the Southern Provinces 

 of the Russian Empire. The species to which his princi- 

 pal 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 run- 

 ning about like messengers among the reposing swarms, 

 ' See Vol. I. 215. 



