14 IMPERFECT SOCIETIES OF INSECTS. 
wards the latter end of last July, walking through a wheat- 
field, I observed that all the blossoms of Convolvulus 
arvensis, though very numerous, were interiorly turned 
quite black by the infinite number of these insects, 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 al- 
ready alluded under the head of emigrations—you per- 
ceive 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 appearance of de- 
sign, 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 prin- 
cipal attention was paid appears to have been the Gryllus 
ttalicus, in its larva and pupa states. “ 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, 
which are lying partly compressed upon the ground, at 
the side of small eminences, and partly attached to tall 
4 See Von. I. 4th Ed. 212, 
