76 PERFECT SOCIETIES OF INSECTS. 



but whether these, like the Clavigers, are subservient to the 

 purposes of the ants, or whether they make the ants subser- 

 vient to theirs, or what is the precise object of the companion- 

 ship, must be left for future investigation, and are points to 

 which I would strongly recommend your attention. 1 



When the population exceeds the produce of a country, or 

 its inhabitants suffer oppression, or are not comfortable in it, 

 emigrations frequently take place, and colonies issue forth to 

 settle in other parts of the globe ; and sometimes whole na- 

 tions leave their own country, either driven to this step by 

 their enemies, or excited by cupidity to take possession of 

 what appears to them a more desirable residence. These 

 motives operate strongly on some insects of the social tribes. 

 Bees and ants are particularly influenced by them. The 

 former, confined in a narrow hive, when their society becomes 

 too numerous to be contained conveniently in it, must neces- 

 sarily send forth the redundant part of their population to 

 seek for new quarters; and the latter — though they usually 

 can enlarge their dwelling to any dimensions which their 

 numbers may require, and therefore do not send forth colonies, 

 unless we may distinguish by that name the departure of the 

 males and females from the nest — are often disgusted with 

 their present habitation, and seek to establish themselves in a 

 new one : — either the near neighbourhood of enemies of 

 their own species ; annoyance from frequent attacks of man 

 or other animals ; their exposure to cold or wet from the 

 removal of some species of shelter; or the discovery of a 

 station better circumstanced or more abundant in aphides ; — 

 all these may operate as inducements to them to change their 

 residence. That this is the case might be inferred from the 

 circumstance noticed by Gould 2 , which I have also partly wit- 



1 As there can be little doubt that several of M. Chevrolat's insects might be 

 found in ants' nests in this country, as well as Claviger foveolatus, if sought for 

 in the way which this indefatigable entomologist employs, it may not be amiss 

 to indicate his mode of procedure. Before attacking an ants' nest he ties the 

 legs of his pantaloons over his boots and puts on gloves, and then proceeds to 

 shovel the whole contents of the nest (of course to the very bottom) into a bag, 

 of the contents of which he spreads successive portions upon a cloth so as to allow 

 the ants to escape, and afterwards examines what remains at his leisure. M. 

 Markel has recently published a memoir on the coleopterous insects found in 

 ants' nests in Saxon Switzerland, amounting to nearly fifty species. (Germar's 

 Zeitschrift, iii. 203.) 



2 Gould, 42. 



