THE NEKVOUS SYSTEM AND THE EYES. 



127 



assume that they really belong to these latter .segments, that is, to 

 segments /// and IV. The next three ganglia {5Gng.^ GGiig., and 

 7G'ng) lie in the segments they innervate (F, F/, and VII) and, 

 hence, belong to the fifth, sixth, and seventh abdominal segments. 

 The last, that is, the seventh ganglion, supplies all of the segments 

 behind it with nerves and is therefore probably a compound of the 

 ganglia originally belonging to the seventh, eighth, ninth, and tenth 

 segments. 



In connection with the nervous system it is most convenient to 

 give a description of the simple and compound eyes. The other 



nner ch. 



Fig. 54. — Horizontal section of compound eye and optic lobe of worker (after Piiillips) : 

 BM, iDasement membrane ; Cor, cornea ; fmi, fm-^, /wis, outer, middle, and inner fibrillar 

 bodies of optic lobe; innvr ch, inner chiasma ; Oiii, ommatidium ; Oi)L, optic lobe; outer 

 ch, outer chiasma. 



sense organs will be found already described along with the parts 

 on Avliich they are located (see })p. 3(5 and 52). All the sense organs, 

 to be sure, are of ectodermal formation and are only secondarily 

 connected with the nervous S3'stem, but the eyes are so intimately 

 associated with the optic lobes of the brain that their description 

 here seems most ap})ro2)riate. 



The compound eye of the bee (figs. 9 A, 10, 52, and 53, E) has been 

 specially studied by Phillips (1005) and figures 51 and 55 are re- 

 produced from his drawings, while the following statements are 

 based on his paper: The convex outer surface or cornea of the eye 



