110 



with the humming-bird hawk-moth (Macroglossa stellatarum), 

 the agent in its fertilisation ( x 6'5) ; 4, Section and view of a 

 ripe anther opening ( x 60) ; 5, Pollen grains adhering by their 

 oil-drops (x 1000). 



PLATE XXXIV. Lilium Martagon. B. 1, Vertical section of 

 the fertilised stigma (x 1150); 2, Ovary, style, and fertilised 

 stigma ( x 9) ; 3, Transverse section of the ovary ( x 36) ; 4, 

 Pollen grains emitting tubes ( x 1100) : 5, Transverse section of 

 a similar grain ( x 2000) ; 6, Longitudinal section of the ovule 

 (x 350). 



PLATE XXXV. Narcissus poeticus. 1, Plant ( x 1) ; 2, 

 Section of the ovule ( x 720) ; 3, Longitudinal section of the 

 flower ( x 1) ; 4, Longitudinal section of the ovary and lower part 

 of the perianth ( x 8) ; 5, Transverse section of the ovary ( x 8). 



PLATE XXXVI. Ophrys arachnites. 1, Upper part of stem 

 showing front and side views of flower ( x 20) ; 2, General 

 view of the plant in flower (x 3); 3, Front view of the 

 stamen ( x 30) ; 4, Pollinium which has been artificially removed 

 by a pencil ( x 30). 



PLATE XXXVII. Passiflora sp, 1, Opened flower of hybrid 

 P. ccerulea-alata ( x 6) ; 2, Median section of an opened flower 

 P. ccerulea ( x 8) ; 3, Fragment of a flower-bearing branch of 

 the hybrid ( x 1) ; 4, Fragment of fruit-bearing branch of 

 P. ccerulea ( x 1). 



PLATE XXXVIII. Cydonia vulgaris. 1, Flower-bearing 

 branch ( x 1) ; 2, Open flower with honey-bee, the agent in its 

 fertilisation ( x 8'5) ; 3, Section through a mature flower ( x 20) ; 

 4, Ilipe fruit ( x 1) ; 5, Longitudinal section of the same ; 6, 

 Transverse section of the same. 



PLATE XXXIX. Phaseolus coccineus, 1, Upper part of a 

 plant ( x 1) ; 2, Part of an inflorescence with bee (Hylceus qua- 

 dricinctus), the agent in its fertilisation ( x 5) ; 3, Open flower, 

 with hole made by the bee ( x 5) ; 4, Flower opened to show its 

 structure ( x 8) ; 5, Keel ( x 25) ; 6, Vertical section of open 

 flower ( x 50) ; 7, Upper end of style ( x 50) ; 8, Branch and 

 raceme ( x 1). 



PLATE XL. Salvia Sclarea. 1, Side view of flower visited by 

 an insect (Xylocopa vidacea] ( x 15) ; 2, Mechanical contrivances 

 for ensuring cross-fertilisation ( x 9j. 



Salvia pratensis. 3, Flower seen from the side ( x 6) ; 4, Me- 

 chanical arrangement of the stamens ( x 6) ; 5, head of the bee 

 (Bombus horiorum), which is the chief agent in fertilising this 

 species. 



PLATE XLI. Centaurea Cyanus. 1, Part of the plant with 

 insects (Empis livida and Plusia gamma) seeking honey ( x 4'5) ; 

 2, Section of an open flower-head ( x 24) ; 3, Flower in the 

 male condition ( x 70) ; 4, Upper part of the style in the female 

 (x 130); 5, Ripe fruit (x 25). 



