Further Publications on the Revegetation of Krakatao

Abstract

This paper very shortly describes 24 galls found on 19 species of plants. Of these 24 galls 13 are caused by mites, 7 by gnats¹⁾, 3 by Psyllidae and one by a species of Aphis. The animals acting as agents are not described at all and not any light is shed on the manner in which they came over to Krakatao; only vague possibilities are discussed. Mr. Docters van Leeuwen cites as a remarkable fact²⁾ that a Psyllida-gall was found on Thespesia lampas. This is certainly remarkable, for Thespesia lampas, a shrub of teak-forests and grassy jungles in regions with a well-marked east-monsoon, was never yet found on any of the islands of the Krakatao-group, which form a very unfit habitat for it. The same author asserts that „he did find it in a „table of plants³⁾ found by Dr. Valeton in 1904”. But this is hardly possible, as Dr. Valeton visited Krakatao not in 1904 but in March 1905 (see Chapter VII) and the only species of Thespesia mentioned by him is Th. populnea Soland ⁴⁾, a sea-side tree of which he found young specimens. Dr. Docters van Leeuwen states that he found Th. lampas on Verlaten Eiland but, as it appears from the lists published elsewhere by him⁵⁾, it was not this species he found but Th. populnea.