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iulus, are all of solitary habits. Some rare insects 
of the genera papilio and phaleena® are usually found 
single or in pairs: even those which are numerous 
can hardly be said to be social. But on imperfect 
and perfect societies of insects such ample and in- 
teresting detail is given by Kirby and Spence, vol. ii. 
that a reference to that excellent work may here 
suffice ; with the bare remark, that ants and bees 
afford the most remarkable instances of perfect so- 
cieties. Some however appear to have solitary ha- 
bits, as the mason bee. The apiarian tribe is divided 
into two subdivisions, the solitary and the social: 
among the former is the genus xylocopa, among 
the latter, eminently, apis mellifica. Crabs are, in 
some species, of solitary habits, as the cancer Bern- 
hardus, or hermit, which having an unprotected tail 
takes shelter in deserted shells of univalves, chiefly 
buccina ; and pinnotheres, which inhabits the beard 
of the pinna. In some, the habits are notoriously 
social, as in the ruricola, or land-crab, so numerous 
in the Bahama islands; and cancer crangon, the 
shrimp or prawn so well known on our coasts. Of 
fish, the solitary habits of some, and the social of 
others may be witnessed by any who ever look into 
a clear stream. The trout and the pike may be 
h Papilio cardui, painted lady: the caterpillar is solitary; the 
butterfly lays a single egg on a leaf:—the caterpillar unites toge- 
ther the edges of the thistle leaf, and feeds on the upper surface. 
Papilio iris, purple emperor, flies high over the summits of oak- 
trees. This, as well as the papilio populi and papilio antiopa, is 
rare, at least in England. 
