166 ARCTIID^. 
scribe a definite line of boundary. The character- 
istic peculiarity of the Arctiidse, however, is, that 
they have the wings deflexed in repose, the posterior 
pair not extending beyond the costa of the anterior, 
and they are connected together by an apparatus 
consisting of a kind of ring in the one which re- 
ceives an elastic spine from the other, thus forming 
a connexion, but still admitting of considerable in- 
dependent motion. The antennae are bipectinated, 
sometimes serrated ; palpi rather small, mostly tri- 
articulate ; spiral tongue generally short, and some 
times altogether wanting. The caterpillars of the 
more typical species are densely clothed with hairs ; 
sometimes with long fascicles or tufts of peculiarly 
formed hairs ; and in some cases they are naked. 
They feed externally on plants. 
This family corresponds to the Faux-Bombyx 
( Pseudo-Bomhyces) of Latreille. It comprehends 
a great number of species, many of which are con- 
spicuous from their rich colouring, but they never 
make any approach to the size of the gigantic 
Bombycida;. 
