LEPIDOPTEROUS INSECTS. 115 
or like the tiles on a roof; the shafts towards the 
body of the insect, and the expansion towards the 
end of the wing, reflecting often the most beautiful 
colours. The eyes are reticulated and large ; and, 
besides these, some have two or three stemmata 
situated on the forehead. The palpi have from two 
to three articulations ; they are hairy, standing out- 
wards, and sometimes a little upwards. Butterflies, 
with their spiral tongues, suck the nectareous juices 
of flowers ; but, in general, they need little food ; 
some, indeed, whose tongue is very short, seem to 
take no nourishment at all. They have, on each 
side, nine spiracula, or organs of respiration, of which 
one is situated on the thorax, the other eight on the 
segments of the abdomen ; the last segment is with- 
out any. The principal function of the perfect insect 
is to propagate its species, for which purpose the 
female, from a peculiar instinct, deposits her eggs on 
such plants, and in such places, as afford the proper 
nourishment to the larva when excluded; after which 
both sexes soon cease to live. 
a pupa, was subjected to the same mode of investigation, when 
it was found to be nine and a quarter times finer than that of 
the perfect insect; and that the square inch contained nine 
hundred and thirty-one thousand eight hundred and eight 
scales to the square inch. So that this natural mosaic must 
be above ten hundred and sixty-three times finer than the 
mosaic of the boasted pictures of modern Rome, where in- 
genuity, animated by zeal, has exerted its utmost efforts, 
