76 
of the leaf is dotted with hundreds of small pustules, measuring 
from 1/, to 2 mM. (see fig. 14), of a dark green hue. On the 
underside of the leaf no- 
thing is visible of the 
galls but clear-white spots 
consisting of hairlets. As 
- a matter of fact the 
pustules are quite hol- 
low on the underside 
and their interior is co- 
vered with white hairs 
of a silverly gloss. They 
are extremely thin and 
uni-cellular, but ve 
long spirally wound. As they completely fill the gall-chamber 
and even protude beyond it, the naked eye perceives nothing 
of the cavity. The plant was found for the first time on Ernst’s 
excursion; it is now one of the most prevalent little trees on 
these islands. The gall also made its appearance there years 
ago, for in the herbarium I found specimens collected by 
Vareton and Backer, bearing the galls in question. 
Island of Krakatau. Ta. Vateron, coll. March 1 st, 1905; C. 
A. Backer coll. April 1906; collected by me in the Casuary- 
grove, Herb. N°. 3542, April 24th 1919; Verlaten-Island, 
C. A. Backer coll. April 1906; by me, Herb. N°. 3724, 
April 27th 1919. 
Literature: 1) og VIL. Bull. d. Jard. Botan. de Buitenzorg. Série II. 
N°. XV. 1914. N°. 480, p. 
2) eos von Celebes ete. Idem N°. XXI, 1916. N°. 50. Fig. 50, 
ee 
Fig. 14. Pipturus incanus Wedd. 
N°. 15. Pithecolobium umbellatum Bth. 
1 ik leet -gall caused by a mite. 
. 2 A usual 1 phenomenon on this species of tree, which is very 
revalent on home, shore. Sometimes nearly all the leaves 
. Described epee as found on Java Ls and oes 
