Abstract
The morphology of the terminal larvae of three species of Megastigmus parasitoids of gall-wasps (Hym., Cynipidae) in Europe, M. dorsalis, M. stigmatizans and M. dumicola, is described for the first time based on SEM images. Larvae of two phytophagous, seed-infesting species of this genus, M. pistaciae and M. aculeatus, are also described and compared with the larvae of the parasitoid species. The morphological characters that differentiate larvae of Megastigmus from other torymid larvae include: strong mandibles bearing four or five teeth, labrum fringed on the anterior margin, and reduced pilosity on the body and head. A key for the identification of the larvae of the five study species is presented. The larvae of the entomophagous Megastigmus species share an important diagnostic character, a deep medial frontal pit not present in the larvae of the seed-infesting species. Biological data of the species studied are discussed and illustrated with digital photographs. While the larvae of M. dumicola are parasitic in twig galls of species of Plagiotrochus on evergreen oaks of the section Ilex, M. dorsalis and M. stigmatizans are associated with galls of many cynipid genera induced on Quercus of the section Quercus.References
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