86 ON THE ANATOMY OF THE FLY. 



intermediate between the cortical and axis cylinders of the 

 rods are nerve tissue, expanding into retinae between the 

 pigmentary and transparent portions of the cones, and con- 

 necting these partial retinee with the common retina beneath. 

 On the other hand it is, perhaps, the common retina which 

 receives the picture, the whole of the rods and cones being 



DESCRIPTION OF PLATE VIII. 



Fig. 1. A small portion of the compound cornea, x 300 diam. 



Fig. 2. The epineuron of tho right eye, seen from within, with part of 

 its muscle, x 25 diam. 



Fig. 3. The haltere, seen from abov- . x 100 diam. 



Fig. 4. A portion of one of the cylinders, from the base of the haltere. 

 X 600 diam. 



Fig. 5. A portion of one of the dome segments, from the base of the 

 halteres. x 500 diam. 



Fig. 6. Section of one of the cylinders, showing the otoconia and nerve 

 c -11s and fibres beneath its ridges, x 500 diam. 



Fig. 7. A small portion of the subcostal neivure, showing pait of a 

 row of wing organs, x 300 diam. 



Fig. 8. The antenna of the light side, x 50 diarn. 

 Fig. 9. First joint of the same, x 75 diam. 

 Fig. 10. Second joint of the same. X 75. 



Fig. 11. Diagramatic i epresentation of a componnd sacculus, from 

 the third joint of the antenna, seen fiom above. 



Fig. 12. Diagramatic section of the wall of the third joint of the 

 antenna, showing one of the compound and two simple sacculi- 



Fig. 13. Terminal branches of antennal nerve, from the third joint of 

 the antenna, x about 500 diam. 



Fig. 14. A small portion of the frontal sac, showing its papillae 

 X 750 diam. 



Fig. 15. A small portion of the maxillary palpus, showing its saccu- 

 lar organs, x 200 diam, 



Fig, 16, One blade of the cephalo-steinum. x 300 diam. 



