OLFACTORY ORGANS OF A COLEOPTEROUS LARVA 



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In sections, more or less of the sense fiber (fig, 1, SF) is always 

 present. Just before entering the pore aperture, it expand > in a 

 clublike manner; the other end of it passes through the pore 

 cavity (fig. 3, PorCav) and unites with the body of the sense cell 

 (fig. 1, SC), which lies in the hypodermis {Hyp). The hypoder- 



Figs. 1 to 13. Cross sections of single olfactory organs, showing internal 

 anatomy, including darker chitin (represented by solid black), lighter chitin 

 (represented by lines), pore aperture (PorAp), pore cavity (PorCav), chitinous 

 cone (Con), sense fiber (SB), sense cell (SC), and hypodermis (Hyp), X 500. 

 Fig. 1 is from antenna; fig. 2, from maxilla; fig. 3, from maxillary palpus; fig. 4, 

 from labial palpus; fig. 5, from mandible (caustic potash preparation); fig. 6, from 

 labrum; fig. 7, from epicranium; fig. 8, from hypopleural region; fig. 9, from coxa; 

 fig. 10, from trochanter; fig. 11, from femur; fig. 12, from tibia; and fig. 13, from 

 tarsus. Figs. 5, 7 and 8 were cut too obliquely to show all of pore cavities. 



mis usually sends prolongations into the pore cayity and some of 

 these unite with the bottom of the chitinous cone (fig. 2, Con), 

 indicating that a hypodermal secretion passed through these 

 prolongations to form the cone. Hypodermal prolongations have 

 been seen in most of the olfactory pores observed in adult insects, 



