IMPERFECT SOCIETIES OF INSECTS. 291 



certain circumstances, merely for the sake of company ; again, others are 

 brought together by accidental causes, and disperse when these cease to 

 operate ; and, finally, others, which may be said to form proper societies, 

 are associated for the nurture of their young, and, by the union of their 

 labours and instincts, for mutual society, help and comfort in erecting or 

 repairing their common habitation, in collecting provisions, and in defending 

 their fortress when attacked. 



With respect to the duration of the societies of insects, some last only 

 during their first or larva state, and are occasionally even restricted to its 

 earliest period ; some again only associate in their perfect or imago state ; 

 while with others, the proper societies for instance, the association is for 

 life. But if I divide societies of insects into perfect and imperfect, it will, 

 I think, enable me to give you a clearer and better view of the subject. 

 By perfect societies I mean those that are associated in all their states, live 

 in a common habitation, and unite their labours to promote a common 

 object ; and by imperfect societies, those that are either associated during 

 part of their existence only, or else do not dwell in a common habitation, 

 nor unite their labours to promote a common object. In the present 

 letter I shall confine myself to giving you some account of imperfect 

 societies. 



Imperfect societies may be considered as of five descriptions : associa- 

 tions for the sake of company only; associations of males during the 

 season for pairing ; associations formed for the purpose of travelling or 

 emigrating together; associations for feeding together ; and associations 

 that undertake some common work. 



The first of these associations consists chiefly of insects in their perfect 

 state. The little beetles called whirlwigs (Gyrinus), which may be seen 

 clustering in groups under warm banks in every river and every pool, and 

 wheeling round and round with great velocity, at your approach dispersing 

 and diving under water, but as soon as you retire resuming their accustomed 

 movements, seem to be under the influence of the social principle, and to 

 form their assemblies for no other purpose than to enjoy together, in the 

 sunbeam, the mazy dance. Impelled by the same feeling, in the very depth 

 of winter, even when the earth is covered with snow, the tribes of Tipularice 

 (usually, but improperly, called gnats) assemble in sheltered situations at 

 mid-day, when the sun shines, and form themselves into choirs, that 

 alternately rise and fall with rapid evolutions. 1 To see these little aery 

 beings apparently so full of joy and life, and feeling the entire force of the 

 social principle in that dreary season, when the whole animal creation 

 appears to suffer, and the rest of the insect tribes are torpid, always con- 

 veys to my mind the most agreeable sensations. These little creatures 

 may always be seen at all seasons amusing themselves with these choral 

 dances, which Mr. Wordsworth, in one of his poems 2 , has alluded to in 

 the following beautiful lines : 



" Nor wanting here to entertain the thought, 

 Creatures that in communities exist 

 Less, as might seem, for general guardianship 

 Or through dependence upon mutual aid, 

 Than by participation of delight, 

 And a strict love of fellowship combined. 



i See also Markwick in White's Nat. Hist. ii. 256. 2 The Excursion. 



u 2 



