IN THE ANTENNA OF INSECTS. 153 



EXPLANATION OF THE PLATES. 



(All the figures are magnified.) 



Tab. XXIX. 



Fig. 1. Antenna of the Blowfly, Musca vomitoria : — a, antenna, showing both the smaller organs and the 

 chambers ; b 1, the smaller organs, having a diameter of 7^5^11 of an inch ; h 2, the apertures to 

 the chambers, having a diameter of ywjtu to yt7» of an inch ; c, aperture of chambers ; c', ditto 

 as seen focused lower down; d, section of wall of antenna, showing 1, the smaller organs, and 

 2, the chambers and their sacculi, the diameter of the largest being ^-ju of an inch. 



Fig. 2. Antenna of Helophilus pendulus: — a, antenna; b 1, the smaller organs, having a diameter of x'h's 

 of an inch ; c 1, do. do. ; c 2, apertures to chambers, diameter xsVij of an inch ; c 2», do. do. 

 focused lower down; c 2'', focused still lower; d, section showing the smaller organs at 1, 

 and the chambers with their sacculi at 2. 



Fig. 3. Antenna of Tabanus bovinus : — a, antenna, with the third to the eighth joints furnished with the 

 organs ; b, enlarged view of the organs of various sizes. 



Fig. 4. a, Antenna of Tipula oleracea ; b, antenna of Ctenophora ? ; c, antenna of Clenophora bima- 



culata; d, section of organs; d, organs as seen from above, diameter jiVo of an inch. 



Fig. 5. Antenna oi Argynnis paphia : — a, antenna showing the position of the organs ; 6 ], small closed 

 perforations of various sizes, the smallest 5 „'„ n , the largest ^^ of an inch ; b 2, openings to 

 cavities, from ysVu to ^xtrff of an inch; c, last joint of the antenna, showing the openings to the 

 cavities ; d, section of chambered cavities, with a projection or papilla in the centre of each. 



Tab. XXX. 



Fig. 6. a, Part of antenna of Apis mellifica ; a 1, groups of organs; a 2, nerve giving off branches; b, 



view of organs, more highly magnified. 

 Fig. 7- o. One joint of antenna of Eucera longtcornis ; b, saucer-shaped depressions, diameter from edge to 



fidge ttVit of an inch ; c, section of wall of antenna, showing sacs or cells beneath ; c 1, membrane 



closing in the openings in internal membrane, diameter tiW of an inch. 

 Fig. 8. a. One joint of antenna of Andrena fulva ; b 1, saucer-like depressions, with membrane in centre 



closing in the perforations ; b 2, hairs ; 1 and 2 are both surrounded by a ring of very minute 



tubercles ; c, section of wall of antenna. 

 Fig 9. a, One joint of antenna of a species of Ichneumon ; b, section of wall of antenna, showing the 



transparent membrane overarching and extending beyond the perforation of the internal wall; 



c, enlarged view of organs ; membrane as seen from above, very transparent, stretching over 



like an inverted canoe ; the opening beneath is the perforation of the internal membrane. 

 Fig. 10. a, Antenna of Libellula depressa, showing the 3rd to the 5th joints with organs placed on one 



side of the nerve ; b, portion of wall of the 3rd joint ; b 1, large sacs with plicated walls, closed 



externally by a delicate membrane ; b 2, small simple sacs, also closed by membrane ; b 3, nerve 



proceeding to sacs ; c, sacs of 5th joint. 

 VOL. XXII. X 



