28 HOW PLANTS EMPLOY INSECTS TO WOllK FOR THEM, 



the honey-tube, its mouth opening just behind the base of this petal. Only the 

 lower half of the tube, more enlarged and capacious, gets filled with nectar. To 



drain a cup which is about an inch and a half 

 deep requires a long proboscis, much longer 

 than any bee or wasp possesses. Butterflies 

 and moths are our only insects capable of do- 

 ing it ; and one could predict from a view of 

 the flower that the work is done by them. In 

 fact we have hardly a butterfly with proboscis 

 long enough to reach the bottom of the cup : 

 so we conclude that one of the Sphynxes or 

 Night-moths, such as flock around the blos- 

 soms of the largest Evening-Primroses at dusk, 

 is the proper helpmate of tjie Greater Green 

 Orchis. The Smaller Green Orchis is much 

 like the Larger, but with honey-tube hardly an 

 Fig. 20. sidcTiewof headofamoth(Sphynx iuch long. This may be drained by many of 

 ^flfnXii' Jnif^^f " ''""^'"' * onr butterflies. Some of these have been 



pair of Orcbis pollen-masses. 



caught with a remarkable body attached to 

 their great eyes, one on each eye ; on exam- 

 ination this body proved to be quite like that 

 represented in Fig. 18, only smaller. This 

 body, as we have seen, is the pollen of one 

 of the cells of an Orchis anther, with its 

 stalk and sticky disk, the latter adhering to 

 the insect's eye. How did it get there 1 

 57. The centre of the flower (as in Fig. 

 rig.M Front Tiewofthe same, with the pollen- iQ\ jg occupied by the One large anther, and 



mariseb in the position they soon take. Both / r ^ 



. flgnres magnified to the same degree as is the by the COncave Stigma. The anther is of 



ig. . ^^^ cells, which taper towards the front of 



the flower and diverge, in this species widely, and the whole space between the 

 two diverging horns on the sides and the orifice of the honey-tube below is stigma, 

 a broad patch of glutinous surface. At the tip of each horn of the anther, facing 

 forwards and partly inwards is the button-shaped, sticky disk. Bring the point 

 of a blunt pencil, or the tip of the little finger, or anything of the proper size, 



