LIST OF ILLUSTRATIONS. xiii 



PIOUBB PAGE 



26. Shows three of Wolffs cups, each with a central hair, a chitinous 



ring, and a double ganglionic swelling terminating in a nerve- 

 fibre, X 500 times. S, R', Sensory pits and hairs ; G, G, 

 ganglionic swelling of nerve .. .. .. .. ..27 



27. Under side of left maxilla of Vespa. 6m, Tnste-cups ; SAm, pro- 



tecting hairs; Tb, tactile hairs; Mt, base of maxillary palpus 28 



28. Section through n taste-cup. SK, Supporting cone ; N, nerve ; 



SZ, sense-cell 28 



29. Tip of the proboscis in the hive bee (Apis), X 140. L, Terminal 



ladle ; Gsy taste-hairs ; Sh, guard-hairs ; Hb, hooked hairs . . 29 



30. Organ of taste of fly (^Musca vcymitoria). gn, Nerve ; gg, ganglion ; 



ax, axe-cylinder ; jo, terminal cylinder; g'A, terminal cone .. 30 



31. Epithelial and (B) olfactory cells of man . . .. .. ..33 



32. Cells from the olfactory region of a proteus (after Strieker), a, 



Epithelial cells ; 6, the apparent processes ; c, olfactory cells. 



A, cilise . , . . . . . , . . . . . . . . 33 



33. Section through the head segment of Polyophthalmus, X 300. 



Imdf muscle ; bo, cup-shaped organ ; cm, cuticle ; kp, hypo- 

 derm ; Imd, longitudinal dorsal muscle ; ■«, peripheral nerve ; 

 6, cerebral ganglion ; cz, commissure of brain ; mb, membrane ; 

 pmg, pigment cells ; Iipdz, unicellular glands in the hypoderm ; 

 gn, brain ; i, nuclei in the brain ■ . . . . . . . . 34 



34. Antenna of Pontella Bairdii (Lubbock) . . . . . . . . 47 



35. Terminal segments of one of the smaller antenuEe of the water- 



woodlouse (Asellus aquaticus), X 500. u, Ordinary hairs (not 

 connected with a nerve) ; 6, hairs of touch (with a nerve at 

 the base) ; o, special cylinders (olfactory cylinders) . . . . 48 



36. Tip of the antenna of a centipede (Julus terrestris), X 600. At 



the apex are four olfactory cylinders, a h\\ of which are also 

 seen on the following segment, among the ordinary hairs . . 49 



37. End of a palpus of Staphylinus erythropterus, X 600. a. Olfac- 



tory pit . . . . . . . . . . . . . . . 50 



38. Part of antenna of Callianassa subterranea. b, Olfactory hairs ; 



g, peculiar curved hairs . . . . . . . . . . . . 50 



39. Terminations of olfactory hairs of Crustacea, a, Of larva of a 



Palcemou ; 6, of a Fagurus ; c, of a Pinnotheres ; d, of a Squilla ; 



e, of a Pontonia . . . . . . . . . . . . . . 51 



40. Antenna of blowfly, u, Enlarged third segment, showing pits ; 



0, base of the antenna . . . . . . . . . . . . 53 



41. One segment of the antenna of an Ichneumon . . . . . . 54 



42. Section through part of the antenna of a wasp, X 430. CH, 



Chitinous skin ; Z, olfactory cone ; G, olfactory pit ; TB, tac- 



