118 



VIEWS OF THE MICROSCOPIC WORLD. 



Fig. 186. 





with no less than four of these wonderfully complex organs, the ordinary pair 

 being of a brown color, while the additional pair, shining with a beautiful 

 citron hue, rise side by side from the upper part of the 

 head. The form of the single lenses in reticulated eyes 

 is not the same in every insect endowed with this curious 

 organ ; for in the compound eye of the dragon-fly and 

 honey-bee, the lenses are six-sided ; while in that of the 

 j lobster they possess a square form. In figure 186 is 

 shown a portion of the cornea of the compound eye of 

 a dragon-fly, the single eyes of which are seen to be six- 

 sided, and regular hexagons. In certain positions, in re- 

 spect to the direction of the light, they gleam with a rich 

 golden hue, and three parallel borders are discerned, which 

 divide the single eyes from each other. The inner circle 

 in figure 18*7 represents the same object of its natural size. Figure 188 pre- 

 sents a magnified view of a part of the complex eye of 

 a lobster, composed of a great number of single eyes, 

 possessing a square form ; the real size of the object is 

 shown by the smaller circle in figure 189. 



The eyes of the bee, which are delineated in figure 

 190, are described by Swammerdam as being profusely 

 covered with hairs, which pierce through the outer cov- 

 ering of the eye, in the same manner as the hairs of the 

 human body penetrate through the skin. These hairs 

 are very numerous, bristling in thick profusion over the 

 .J e y e? and are supposed to perform the office of eye-lashes 

 Fig- !89. or eve _b rowSj in protecting the organ from dust, or 

 any similar annoyances that might work it harm. In this figure, the com- 

 pound eyes of the bee, with the parts adjacent, are beautifully and distinctly 

 revealed. 



The upper part of the wood cut exhibits one of the eyes in its perfect state, 

 composed of hexagonal lenses, and bristling with hair. In the lower por- 

 tion of the same figure, the other complex eye is shown, deprived of some of 

 its hexagonal lenses in order that its structure may be perceived : the lenses or 

 single eyes are here seen to have the shape of a pyramid. The three oval 

 figures, 'situated together in the angle formed by the two compound eyes are 

 the coronet eyes of the insect, while the two branching members that curve over 

 the reticulated eyes, are the antennaa of the bee. Between these the head is 

 thickly covered with plumes of hair. Figures 191 and 192, represent seven of 

 the hexagonal lenses, very highly magnified, and which, in 192 are exhibited 

 bristling with hair. 



