142 



THE SENSE ORGANS 



[CH. 



are easily made out in the eye of the freshly-emerged imago. The 

 corneal lens is slightly biconvex, and is made up of a thinner outer 

 layer, which stains deeply with eosin, and a thicker inner layer 



fm 



Fig. 62. L.S. through four ommatidia from fig. 58 ( x 330). At A-O are shewn 

 seven T.S. through one ommatidium at the respective levels at which they 

 are placed, cng corneagen cells; cnl corneal lens; / facet; fm fenestrate 

 membrane; ir primary, ir' secondary iris cells; Im lumen; ns nucleus of 

 Semper; pc pseudocone; rh rhabdome; rp retinal pigment; rt retinal cell; 

 tr trachea. Original. 



not so easily stained. This inner layer is found to be in reality 

 made up of several fine laminae superimposed one upon another. 



