Young galls are often reddish at the base, with the rest of the gall being green. Over time the galls gradually change from light green to light brown and eventually a darker brown. Galls are easily removed from the cavities in which they are embedded, similar to the fruit.Mature galls were about 11 mm in length and 2 mm in diameter (measured at the base, where the diameter is greater).The Contarinia larva was located in the basal portion of the gall, which was mostly embedded in the infructescence. At maturity the galls became quite dry, and the tip of the gall became frayed and fibrous, probably loosening the apex and thereby making it easier for the pupa to push through be-fore adult emergence

- RJ Gagne, Juan Manuel Ley-López, Paul E. Hanson: (2018) First New World Record of a Gall Midge from Palms: A New Species of Contarinia (Diptera: Cecidomyiidae) from Geonoma cuneata in Costa Rice^©