XII. FURTHER PUBLICATIONS ON THE REVEGETATION 



OF KRAKATAO. 



A. Dr. W. Docters van Leeuwen, The Galls of Krakatnu and Verlaten Eiland 

 (Desert Island) in 1919, in Ann. lard. Hot. Buitenzorg XXXI (1921), p. 57 seq. 



This paper very shortly describes 24 galls found on 19 species of 

 plants. Of these 24 galls 13 are caused by mites, 7 by gnats *), 

 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 fact 2 ) that a Psyllida-gall was found on 

 Thespesia lampas. This is certainly remarkable, for TJiespesia 

 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 plants ;{ ) 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 So/and '*), 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 him "'), 

 it was not this species he found but Th. populnea. 



Mr. Docters van Leeuwen states"): ,,most of the galls 

 ,,l found on genuine coast-plants or on plants occurring within 

 ,,a short distance of the shore. There it was also that the veget- 

 ,,ation comprised the greatest variety of species. On climbing 

 ,,the mountain-slopes the number of different phanerogamous 

 ,,plants becomes gradually smaller whilst, contrarily, the number of 

 individuals belonging to the same species increases considerably". 



*) In a subsequent paper (Vide sub B) called midges. 



2) I. c. p. 63. 



"') See p. 129, footnote 2. 



4 ) See p. 137, No 31. 



*) Ann. |ard. Bot. Buitenzorg XXXI (1921), pp. 79, 128, 137. 



6 ) Ann. lard. Bot. Buitenzorg XXXI (1921 ), p. 63. 



