ALLUREMENTS OF ANIMALS FOR THE DISPERSION OF POLLEN. 171 



neadow Orchids (Orchis mascula, militaris, Morio, &c.), are pierced and sucked bj' 

 insects, and it should be noted here that not only flies, bees, and humble-bees, but 

 3ven butterflies are capable of boring into juicy tissue. Butterflies have at the end 

 Df their maxillary lamina which compose their proboscis, certain sharp-pointed 

 ippendages with which they first rip up the juicy tissue and then steal the 

 liquid. 



A special allurement to those insects which are accustomed to pierce and suck 

 juicy tissues is observed in species of Eremv/rus {E. altaicus, caucasicus, tauricus), 

 indigenous in Altai, Caucasus, and Taurus. These plants, which belong to the 

 Liliacese, bear a raceme on a long rachis which elongates greatly during flowering. 

 When the flower-buds open the petals are spread out flat, and surround the still 

 closed anthers like a six-rayed star. This only lasts for a short time. As soon as 

 the anthers dehisce and expose their sticky, orange-coloured pollen, the petals roll 

 themselves up, become shrivelled, and form a small dirty red-brown ball, from 

 which spring six thick greenish swellings. These swellings, which are really the 

 juicy veins of the under sides of the petals, resemble green aphides. The fly 

 Syrphus pirastri, which is known to seek for Aphides, pierces and sucks these 

 swellings, apparently mistaking them for the insects; at any rate they pierce the 

 roUed-up flowers of Eremurus just like Aphides, and, what is most wonderful 

 about the matter, they load themselves by this means with the pollen of the anthers 

 standing in front of the flower, and convey it to the stigmas of other flowers. 



We shall have to speak presently of plants whose flowers are only open for a 

 day, a night, sometimes only a few hours. The petals of these plants have this 

 peculiarity, that when they wither they fall quickly, become discoloured, crumpled 

 or rolled up, and pulpy. Then the cell-sap exudes from the tissue and covers 

 the surface with a thin layer of fluid. Pulpy petals of this kind are visited by 

 insects, specially by flies, which lick up and suck the juice, and at the same time 

 cover the stigma with pollen brought from other flowers. This is the case, for 

 example, in Calandrinia, Tradescantia, and Villarsia. This proceeding is an 

 uncommon one, for the simple reason that the number of plants with such short- 

 lived flowers is very limited. 



On the other hand, the secretion of juices on the surfaces of fresh tissues of 

 flowers that remain open several days is a widely-spread phenomenon, so that it is 

 perhaps not too much to say that this secretion occurs in 90 per cent of flowers 

 visited by insects and humming-birds. The secreted juice contains more or less 

 sugar and has a sweet taste. But along with the sugar there are also various other 

 ingredients in solution. According to the variable contents of these ingredients the 

 consistency, the colour, and the smell of the liquid of course vary considerably. 

 Sometimes it is watery and colourless, while at other times it is a thick fluid and 

 brown like treacle. The dark liquid, as it is found in the flowers of Melianthus, 

 has an unpleasant and even an offensive odour. But in most cases the smell is 

 similar to that of bees' honey. For the most part this sweet sap is practically the 

 same as honey, and this name is therefore now given to it by most botanists. 



