AND INSECT AID. 235 



These balls are so viscid that they stick firmly to whatever they 

 touch, and the viscid matter sets hard and dry like cement within 

 a minute or so. As the anther cells are now open in front, when 

 the insect witlidraws its head, or when the pencil is withdrawn, 

 one or both polHnia will be withdrawn firmly attached to the 

 object, sticking up like horns. The firmness of the cement is 

 necessary, for if tlie pollinia were to fall sideways or backwards 

 they would never fertilise the flower. Now let us suppose the 

 insect to fly to another flower, or insert the pencil with the poUinium 

 attached into another nectary. If this be done at once it is evident 

 that the pollinium will be pushed into or against its old place, 

 the anther cell. How then can the flower be fertilised ? This is 

 effected by a very beautiful contrivance. ^\'ithin a minute the 

 pollinia, by the contraction of the minute disc to which they are 

 attached, move downwards to an angle of about 45 degrees from 

 the first upright position. When the insect sucks the next flower 

 the pollen masses come in direct contact with the stigmatic surface. 

 The stigma is so very viscid tliat it is certain to pull off some of 

 these pollen packets and rupture the threads. The whole pollinium 

 is scarcely ever retained by the stigma, so that one pollinium serves 

 to fertilise several flowers. So economical is Nature in her 

 workings that even a few pollen masses are not unwortliy of her 

 sedulous care. 



Of all the pollen-carriers, and consequently flower-fertilisers, 

 bees are the most assiduous. Attracted by the gay colours of the 

 corolla, sweet scent, or the prospect of honey, they visit most 

 flowers that are incapable of self-fertilisation. That bees can 

 distinguish between one colour and another, and that they exhibit 

 a preference for certain colours, has been clearly proved by Sir 

 John Lubbock and others. The bodies of some bees, and the 

 legs of others, are so admirably adapted for the collection and 

 carriage of pollen, that it is almost impossible for them to visit 

 any flower in pursuit of honey without bearing away a large 

 quantity of pollen grains. The body of the humble bee {Bo)nbiis 

 tcrrestris) is the best adapted for pollen carrying. Lepidoptera 

 stand next in order of importance to bees as pollen carriers. 

 Their long proboscides enable them to drain nectaries which less 

 favoured insects cannot reach. The despised wasp is not without 



