THE MONTHLY BULLETIN. 539 



Having proven that a remedy had been found that was effective with- 

 out injury to the plant, it was a matter of detail to work out a plan 

 whereby all the scales could be reached by the solution. At the present 

 time, for offshoots a vat is used that will hold a number which are im- 

 mersed for a short time. This treatment is repeated a few hours later. 

 Nearly all the scale are killed by these two treatments, but not all. In 

 some cases air bubbles form so that the saturation is not complete. In 

 other cases the fiber is drawn so tightly that small spots will occasionally 

 escape treatment and on these dry spots enough live Marlatt's scale will 

 be found to give a good start again. In the case of Blanchard's scale 

 on the offshoots some of the leaves will be folded so closely that all parts 

 are not wet and so occasionally one of these is left unharmed. 



At present, offshoots, treated in this way, are placed in nursery rows 

 under quarantine for twelve months. This is done to watch develop- 

 ments. What the future regulations will be can only be determined by 

 the results of our experiments. The future plans are not definitely 

 worked out, but from experiments thus far carried on it seems reason- 

 ably certain that these pests need never give any serious trouble. 



FUNGUS GARDENS CULTIVATED BY ANTS. 



By H. S. Pawcett. 



One of the most interesting relations that exists between plants and 

 insects is that in which a definite species of fungus is cultivated and 

 tended with the greatest of care for food by the parasol ant of Brazil. 

 Citrus trees, among others, in that region are stripped of their leaves 

 to supply suitable culture media for the chosen fungus. Shimper'- 

 gives a very interesting account of this relation in "Geography of 

 Plants" from which the information in this article is obtained. 



Streams consisting of pieces of foliage of considerable size will be seen 

 traveling in a definite direction. On close inspection these will be seen 

 to be borne on the heads of ants. The pieces are cut from the margins 

 of the leaf by shear-like mandibles, and placed on the head of the ant 

 by a jerking motion and off the ant goes toward the nest. Sometimes the 

 ants are so active as to strip the chosen plant of all foliage except ribs 

 and petiole. They have been known to travel a half mile from their 

 nests to obtain the right species of plant. They select and reject cer- 

 tain plants in turn probably for the purpose of getting just the right 

 mixture. 



A small part of the pieces of foliage is used to line the underground 

 nests, but most of it is cut up again by the ants and kneaded soft by 

 their feet and mandibles, until few cells remain unbruised. This is 

 worked up into a porous spongy mass. This constitutes the fungus 

 garden. Throughout the mass there grows the mycelium of a certain 

 definite species of fungus which the ants always keep alive in their 



'Shimper, Geography of Plants, p. 134. 



