THE SENSES AND SENSE-ORGANS OF INSECTS. 181 



the screen. Whence there is thrown on tlio screen a reduced 

 stippled image, c' d!, of the aiTow. On this view., therefore, 



Fro. 1. 



Sense-Obgans oj? Cbayhsb. 



(From C. Lloyd Morgan's Animal Bioloijy. Fig. 78.) 



A. .Joints near the end of the outer hmb (exopodite) of the antonnule, 



showing tactile setio at a, and olfactory setro at h. 



B. Tactile setro— a. from tho tip of the inner limb (ondopodite) ot tlie 



antennule ; h. from a tutt on the antennulary protopodite on the 

 base of the antennule. Drawn under the microscope. 



C. Olfactory seta3— a. from the side ; h. from above. Drawn under the 



microscope. 



D. Auditory setm from the auditory sac, which lies in tho basal joint of 



the antennule. Drawn under the microscope, s. Grain of sand. 



E. Portion of section of eye. b. m. Basilar membrane ; co. corneal facet ; 



cr. crystalline cone; <j.c. ganglion cells; re./, nerve fibres; re. retinula; 

 St. sp. striated spindle. Drawn under tho microscope. 



F. Diagram to illustrate arthropod vision, a.h. Transparent rods with 



pigment between; c.d. object ; c'.d'. its image on the screen e. f. 



