Ridley.—Symbiosis of Ants mid Plants. 479 
They do not bend downwards, but remain erect till they fall off, and do 
not produce food-bodies. 
The glands are very similar to the food-bodies, white and slightly 
verrucose, but more translucent. The food-bodies are only more borne on 
the sides of the nerves which carry few glands. It is by no means infre¬ 
quent to find plants of M. hypoleuca unprotected by ants, and this is 
especially the case in isolated plants. They appear shabby and weak, and 
almost invariably have the leaves gnawed by caterpillars. 
In such seedlings the stems are swollen between the nodes, and hollow, 
with fragments of pith lying in the hollow, but there are no perforations 
through the nodal septa, and no ants are to be seen about the plants. 
On one of these uninhabited plants I found two caterpillars of different 
species ; one was a Tortricid caterpillar, and with it was a pupa of apparently 
the same species. This caterpillar was concealed below the deflexed young 
leaf which it had much injured. The other larva, on a somewhat older leaf, 
was apparently that of a Bombycid. It was devouring the leaf from the 
under side. Both the caterpillars and the pupa were just where the ants 
would have been if the plant had been inhabited. 
Another young plant which was unprotected was adjacent to a fair¬ 
sized tree, also unprotected. Here again I found the Tortricid larva beneath 
the youngest leaf. Every leaf on this plant had been injured and the plant 
was sickly. Another unprotected plant had the same kind of Tortricid 
caterpillar and a number of larval thrips on the under side of the young 
leaf, and a dead adult thrips lay on an adjacent leaf. The caterpillar had 
spun webs containing its excreta beneath the leaf which was injured. 
As there were many food-bodies beneath this leaf, more than usual, I con¬ 
clude the caterpillar does not eat them. 
Many other unprotected plants in which I did not find any larvae had 
all, or nearly all, their leaves gnawed, but almost all either had caterpillars 
beneath the leaves or had obviously been attacked some time previously. 
Summary of the Notes on Macaranga. 
The trees of this genus may be divided into those which are inhabited 
by ants and those which are not. 
The latter possess solid stems with a small pithy cavity, which is never 
hollowed out; the leaves possess no nectaries, nor are they or the stems 
ever covered with a waxy excretion, but are generally more or less hairy 
or covered, especially when young, by a woolly or felted coating. The 
greater number possess bud-bracts, which, however, usually fall off shortly 
after they are reflexed from the bud, but occasionally persist for some time 
(.Macaranga populifolia). Bladder-glands occur on the leaves of some 
species at least (M. trichocarpa\ but never develop into food-bodies ; they 
seem always to be absent from the bud-bracts. 
