212 OUR INSECT FRIENDS AND FOES 



(D. deltoides) is so nearly closed by the stamens 

 and pistil, that it is only possible for the long 

 and slender proboscis of Lepidopterous insects 

 to reach the honey, and the flower which like 

 the Bulbous Buttercup has a male and female 

 stage, is dependent upon the visits of these 

 insects for the transference of the pollen from 

 the anthers of the younger flowers to the stigmas 

 of the older ones. The stamens are^ten in number, 

 and very shortly after the flower opens, five of 

 them emerge from the tube, ripen, and their 

 anthers open. When these have shed their 

 pollen, the remaining five come to maturity. 

 Then the pistil, which during the ripening of 

 the two sets of anthers had remained concealed 

 in the tube, matures, emerges, and its two long 

 stigmas expand themselves, assuming such a 

 position that they cannot fail to be touched by 

 the visiting pollen-laden insects. 



The beautiful and fragrant flowers of the 

 Sweet Pea offer an interesting example of the 

 remarkable manner in which the Papilionacece, 

 by means of a kind of piston apparatus, pump 

 the pollen on to the visiting winged insect. 

 Everybody is familiar with the general appear- 

 ance of these favourite flowers ; the corolla con- 

 sists of five petals, the upper one called the 

 standard, the two lateral ones forming the wings, 

 and the two lower petals, which are united at 

 their edges into a boat-shaped organ called the 

 keel. Within this keel are the stamens and 

 pistil. When a bee alights on the wings of the 

 flower, her weight presses down the keel, which 

 is locked with the two wings, and some pollen, 



