The junction of the two grooved surfaces that form the tube is effected by the same contrivance that reunites the web of a feather when it has been pulled apart. We all know how completely it is made whole again, and on examining by what means this result is brought about, we find that it is by the interlacing of a {26} number of small fibres or hairs, just as, on a larger scale, a pair of brushes adhere when pressed face to face; and so in the butterfly's sucker, the two edges that join to form the tube are closely set with minute bristles that, when brought together, interlock so closely as to make an air-tight surface. Fig. 9, Plate II., is a transverse section taken near the base of the sucker, the small opening at the top being the food passage, those at the side the air-tubes that supply air for respiration and perhaps assist in suction. The tube is probably made with separable parts in order that if its interior should become at any time clogged by grosser particles drawn up with the flower nectar, it may be opened and cleansed by the insect; otherwise, the tube once rendered impassable, the insect would speedily starve, as this narrow channel is the only inlet for the creature's nourishment--its only mouth, in fact, for no butterfly possesses jaws to bite with, or can take any but the liquid food pumped up by suction through this pipe. At the end of the proboscis--or, as it is called scientifically, the Haustellum[3]--there are visible in some butterflies a number of small projections, of the form shown at fig. 10, Plate II., which is a highly magnified figure of the end of the Red Admiral's proboscis. These appendages are generally supposed to be organs of taste, {27} and to aid in the discrimination of food when the pipe is unrolled and thrust down deep into the nectary of a flower. The _compound eye_ of a butterfly, wonderful as its structure is, does not greatly differ from that of many other insects, being like them composed of an immense number of little lenses set together to form a hemisphere large in comparison with the insect's head. A portion of one of these eyes forms a pretty and interesting object for the microscope, presenting a honey-comb appearance, the hexagonal lines that mark the division of the lenses being most beautifully geometrical and regular in their arrangement. More than seventeen hundred of these lenses have been counted in a single eye, and each of these is considered to possess the qualities of a complete and independent eye. If this be true, the butterfly may be said to be endowed with at least thirty-four thousand eyes! There exist also, as in other insects, _two simple_ eyes, placed on the top of the head, but so buried in down and scales as to be neither visible, nor useful for vision as far as we can perceive; probably the creature finds that his allowance of thirty-four thousand windows to his soul lets in as much light as he requires.