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PACIFIC SCIENCE, VoL XX, October 1966 
Fig. 5. Transverse section through gall showing division of vascular system into separate parts (/, larval 
cavity) . 
from the feeding action of the larva (Bloch, 
1952) and may not represent a permanent cel- 
lular transformation such as appears to be the 
case in crown gall and in animal cancers. Elec- 
tron microscope studies might prove illuminat- 
ing in answering such questions, and should at 
least reveal the presence of any viruses or bac- 
teria which might be associated with the larvae 
and which have not at present been detected. 
Whatever adverse effects the larva and gall 
may have on M. australis , there is no obvious 
sign that translocation or transpiration is seri- 
ously impeded. This is probably because the 
ropelike divisions of the stele which run sepa- 
rately through the gall are united at either end 
and do not disrupt the continuity of the climb- 
ing stems which may extend to great heights. 
SUMMARY 
Stem galls on the liane Muehlenbeckia aus- 
tralis (Forst.f.) are caused by the larval form 
of the moth Morova sub fas data Walk., which 
feeds on proliferating tissue of the pith. 
After the departure of the insect, the gall 
continues to grow without blocking transloca- 
tion or transpiration in the stem. 
Gall formation is brought about by excessive 
growth of the pith, vascular rays, and cambium, 
which separate the vascular cylinder into several 
ropelike portions which remain united at either 
end of the gall. 
Applications of crude acetone extracts of 
young larvae failed to produce galls on seed- 
lings of M. australis grown in a glasshouse. 
