198 The Honey-Makers 



any god. That poetical notion has vanished before the 

 critical eye of science, which has discovered two natural 

 causes for the appearance of the honey-dew. 



One is that under certain conditions certain plants ex- 

 press a sweet sap from their leaves. This may not be 

 " vegetable perspiration which trees emit for their relief 

 in sultry weather,'' but it is sometimes as copious as a pro- 

 fuse perspiration and in some instances at least appears to 

 be the result of abnormal conditions. 



The other source of honey-dew one hesitates to exploit, 

 for while one is willing to accept honey from the "bottle " 

 of a bee, it is another matter to receive it graciously from a 

 plant-louse. For no doubt the greater part of the honey- 

 dew found in such clammy abundance on our tulip and 

 oak trees, even on our apple-trees, on our elm, maple, 

 plane, lime, and cherry-trees, on our hazel, blackberry, and 

 currant bushes, in fact, upon occasion almost anywhere, 

 comes from the little insects known as aphides, — the ants' 

 cows, as they are sometimes called. 



These gourmands attach themselves to the under side of 

 the leaf by the proboscis, and there stay and suck out the 

 juices of the plant, taking the nourishment they need and 

 manufacturing at the same time an excrementitious sub- 

 stance of a sweet taste. 



This honey-dew the ants are very fond of, some species 

 even cultivating the aphides for the sake of having it. The 

 story obtained currency that the ant caressed the aphis with 

 its feelers, when the accommodating " cow " gave forth a 

 drop of the sweet liquid from two little " horns " on its back. 

 To-day we are deprived. of even the small comfort of these 

 " horns," which are shown to excrete, not the sweet honey- 

 dew, but a waxy substance by which to smear the faces and 

 so repel the attacks of insect enemies. The honey-dew 

 then is purely excrementitious, and is elaborated in such 



