OLFACTORY ORGANS OF LEPIDOPTERA 



45 



the domes (fig. 9 B, D) lie below the surface of the surrounding 

 chitin. Neither Guenther ('01) nor Freiling ('09), who have 

 studied the anatomy of these organs, saw the sense fibers pass 

 through the domes, and consequently they speculated about the 

 function of these pores. Owing to the small size of the pore 

 apertures and to the great thickness of the domes the present 



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Fig. 4 External view of olfactory pores of Bombyx mori 9 , showing varia- 

 tions in size, X 320. A, group no. 1; B, 6 of group no. 2; C, 10 of group no. 3; 

 D, 12 of group no. 4; E, 15 of group no. 5; F, 8 of group no. 6; G, group no. 7; 

 H, group no. 8; I, group no. 9; J, group no. 10; K, group no. 11; L, group a and 

 a hair socket (HrSk) ; and M, a hair (Hr), 4 hairs sockets and 4 pores from tip of 

 hind wing on ventral side. Hr, hair, called S. trichodea on antenna; HrSk, 

 hair socket; PorAp, pore aperture; PorB, pore border; PorW, pore wall. 



writer has not been able to find a pore which well illustrated the 

 sense fiber running into the pore aperture, nevertheless four 

 pores (figs. 5 A and D, 8 A and E) were found, each of which 

 had a light streak passing through the dome (D). A few sec- 

 tions cut obliquely clearly show the sense fibers (figs. 7 and 8B) 

 connecting with the pore apertures, so that in the present writer's 

 opinion there can be no doubt about the peripheral ends of the 

 sense fibers coming in direct contact with the external air. 



