230 



Discoveries of Millie?' and other's in the 



or green, in the Orthoptera; brownish yellow, brown, red 

 brown, or green, in the Coleoptera ; and in both these orders 

 it partakes of the general colour of the skin of the insects. 

 It is golden yellow in the Hemerobius perla, and in many 

 dipterous insects. In some of the Diptera and Orthoptera, 

 it is also marked with points and bands of different colours ; 

 a circumstance which will be again noticed. Occasionally its 

 hue varies even in the same genus. 



The deeper or more internal pigment, lying between the 

 apices of the cones, and between the nervous filaments, ex- 

 hibits much fewer diversities of tint in different insects. It 

 differs also from the superficial layer, in its colour being 

 altogether uninfluenced by that of the general covering of 

 the body. Its most remarkable colours are the following: 

 a clear red, in that portion near the apices of the cones in 

 the Mantides ; a red purple in many of the Diptera, as in the 

 common fly ; a violet in the ^latta orientalis ; a violet blue 

 in the Phalae^nae, and in the more internal parts of the eye 

 of the Mantides ; a blue black and black in the bees, and in 

 most of the Coleoptera and Lepidoptera. 



In general the colour becomes darker in proceeding from 

 the exterior to the interior of the eye ; sometimes also 

 brighter tints, or different colours, are observed in this internal 

 portion of the pigment ; this is seen in many of the Orthop- 

 tera, but especially in the Mantides. 



In the Mantis religiosa, the cones near the cornea are 

 invested with a clear yellow brown pigment {^g. 45. a); more 

 internally they are provided with a pigment of a reddish 

 violet hue, which extends beyond the apices of the cones (b). 

 In this section of the eye the cones apparently do not extend 

 to the optic filaments, and the interval seems to be filled 



with this second layer 

 of pigment. Whether 

 any other transparent 

 structure connects the 

 cones with their cor- 

 responding nervous fi- 

 laments, is at present 

 unknown; but, if such 

 be not the case, it 

 must be inferred that 

 this red pigment occu- 

 pying the space be- 

 tween these two sets of 

 organs, is itself trans- 

 parent in the living 



