180 



the Beetlei 

 Worm Mo 

 and in som 

 The appi 

 lontha, Yel 

 fied is show 



Pic. 10G. 



sects such a number of eyes, is 

 evidently that they may be enabled 

 to see in all directions without 

 moving the eye ball or head, as 

 will be shown directly. 



Magnified Eye of a Butterfly. In the Phalena a 

 genus of Butterflies, and in some other tribes, the little 

 eyes are arranged into squares in- 

 stead of hexagons, as shown by Fig. 

 106. The design of this variety in 

 different species is unknown, but un- 

 doubtedly some purpose of conve- 

 nience to the Insect is answered by 

 it. 



Structure of the Compound Eyes of Insects. Natu- 

 ralists have investigated with great care and considera- 

 ble labor the structure of the compound eyes of Insects. 

 The following account of the mechanism of the eye of 

 the Libellula vulgata, or grey Dragon-fly, is the result 

 of the observations of M. Duges, a French naturalist. 

 The figures of course are magnified, some of them 

 many hundred times. 



The whole outside surface of the compound eye c c, 

 Fig. 106, may be considered as corresponding to the 

 cornea of animals. Each separate division of this part 

 in Insects is called corneule, or little cornea. These 

 are shown by the waved line on the circumference of 



