maybe it is also worth to have a look at the following publications
Raman, A., Schaefer, C. W. & Withers, T. M. (2005) Biology, Ecology, and Evolution of Gall-inducing Arthropods. In. Science Publishers, Enfield, Plymouth, p. 817.
Redfern, M. & Askew, R. R. (1992) Plant galls (Vol. 17). Slough: The Richmond Publishing Co. Ltd.
Shorthouse, J. D. & Rohfritsch, O. (1992) Biology of insect-induced galls. In. Oxford University Press, New York, Oxford, p. 285.