OR, MANUAI, OF THB APIARY. 



75 



places. I/arvffi, like spiders and most myriapods, have only 

 simple eyes. 



The compound eyes (Fig. 3) are simply a cluster of simple 

 eyes, so crowded that they are hexagonal (Fig. 20). The cornea 

 or facet (Fig. 20) is transparent, modified, chitinous skin. Just 

 Fig. 23. 



Fig. 24. 



Retinulce of Eye, after Dujardin. 



Longitudinal Section of part 

 of Eye, after Cowan. 



c Facet. 

 n Nuclei. 



cc Cones. 

 r Retinulffi. 



Hods much magnified, 

 after Dujardin. 



within each facet is the crystalline lens (Fig. 22, cc) or crystal- 

 line cone back of which extend the rods (Fig. 21, R, Fig. 23, cc) 

 which consist of chitinous threads. Each rod is surrounded 

 by rounded columns, eight in bees (Fig. 24) — retinulse — which 



