_ Serie II, N°. TH, 1912, p. 2. 
59 
of the fact that the number of individuals of some animals 
in the islands is so enormous. 
Most of the gall-producers found by me belong to the gall- 
mites and the gall-gnats, which, according to my experience of 
many years in studying the galls of Java, are the commonest 
gall-producers in the tropical Macatee Among the 24 gall-pro- 
ducers there are 13 gall-mites, 7 gall-gnats, 3 Psyllidae and 
one Aphis (plant-louse). : 
In Java mite-galls and gnat-galls occur in about equal num- 
ber. But on Krakatau regular moist forests are as yet scarce 
and in a contribution to the knowledge of Java-galls ') I al- 
ready drew attention to the fact that the generally juicy gall- 
gnat-galls abound especially in the moist virgin forests, whilst 
in drier regions it are mito-galls that prevail. Also in the in- 
troduction to the article on galls of Celebes?) the same fact is 
drawn attention to. Zhrips-galls, which are so common in the 
tropics, I did not find at all. 
_ On Krakatau the conditions of the vegetation are still such 
that for some time to come the mite-galls will have more 
chances of development than the Cecidomyide-galls; this is ap-_ 
parent not only in the number of species, but especially in the 
number of individuals to be found of each of the mite-gall 
Species. . 3 
Now the striking fact about this general classification is 
that both gall-mites and gall-gnats belong to the minuter spe-_ 
cies of animals, the mites even to the microscopic types, whe- 
reas the larger gall-makers, such as the moths, were not met 
with by me at all. This may have to be accounted for by the 
absence of the host-plants concerned. I found moth-galls on 20 
species of plants in Java. Of these plants I only found two 
_- Species on Krakatau and Verlaten-Eiland, viz. Aeschynomene ine . 
_ dica and Leea sambucina, both of these in insignificant numbers. 
About the manners and conditions of the spread —— 
2 4) Einige Gales” aus Java. Sechster Beitrag. Bull. d. Jard. Bot. d. Puitenog. oe 
a. 2) Beschrei — von Galhen 2 aus Celebes ete. Idem. N°. ‘XXI, ae Pp ca . = oo 
