HEMIPTEEA. 127 



where plant-lice are gathered together in great numbers. Are 

 ants simply friends of the plant-lice, as thought the ancients ? Or 

 have their visits some selfish object ? 



Linnaeus, Bonnet, and Pierre Huber thought .that the ants did 

 not pay these visits for nothing, and that they had some object in 

 seeking them. But what could they have to ask of the plant-lice ? 

 It is to Pierre Huber we owe the solution of this mystery. This 

 naturalist has made the most beautiful observations on the rela- 

 tions which exist between plant-lice and ants. They are detailed 

 in a chapter of his admirable work, entitled " Hecherches sur les 

 Moaurs des Fourmis indigenes." 



The plant-lice have, as we have said, at the extremity of their 

 abdomen two small movable horns. These are in communication 

 with a little gland which produces a sugary liquid. When one 

 carefully observes plant- lice attached to the stem of a plant, one 

 sees a little syrupy droplet oozing out of the extremity of these 

 tubes. 



M. Morren, who has made some interesting observations on the 

 anatomy and generation of the aphis, says that, having shut 

 up females in wide-mouthed glass bottles, he saw the young, 

 a little time after their birth, suck the sweet juice which exudes 

 from the little tubes at the extremity of the mother's abdomen. 

 This secretion seems, then, destined for the nourishment of the 

 young in the first moments of their existence, before they are able 

 to nourish themselves on vegetable juices. The saccharine fluid 

 produced by the mother must be, then, a sort of milk intended for 

 the nourishment of her young. This being established, listen to 

 what follows. In all places where plant-lice are assembled in great 

 numbers it is easy to observe how excessively fond ants are of the 

 sugary liquid .destined for suckling the young. But how do the 

 ants manage to get the plant-lice to allow themselves to be, as we 

 may say, milked ? 



" It had been already noticed," says this celebrated observer, 

 " that the ants waited for the moment at which the plant-lice caused 

 to come out of their abdomen this precious manna, which they im- 

 mediately seized. But I discovered that this was the least of their 

 talents, and that they also knew how to manage to be served with 

 this liquid at will. This is their secret. A branch of a thistle 



