222 



THE EYE IN EVOLUTION 



Figs. 225 to 227. — The Compound Eyes of Insects. 



Fig. 225. — The head of the dragon-fly, jEschna californica (Odonata) capped 

 by two enormovis crescent-like comiDound eyes (James Needham). 



Fig. 



l&.- 



-The male gadfly, Ancnia fasciata 

 nilotica (Diptera). 



The immense compound eyes occupy the 

 whole of the surface of the head (Natural History 

 Museum, London). 



Fig. 227. — The cave-bug, Leotichius 

 glaucopis (Hemiptera). 



From Malaya. Dorsal surface. The 

 2 prominent compound eyes (C) are 

 largely spread over the ventral surface. 

 There are 2 median ocelli (S) (Natural 

 History Museum, London). 



THE STEMMATA (OR LATERAL OCELLi) OF LARVAL OR PUPAL FORMS 



can in general be classified into two main types. The most elaborate 

 organs are seen in the larvae of Lepidoptera and Trichoptera ; 

 these are arranged in a group of variable size ^ on either side of 

 the Jjcnd, each separate individual of which takes the form of the 

 single itnatidium of a compound eye with a cuticular corneal lens, 



g., 6 on either side of the head in the caterpillars of butterflies. 



