The aim of the collection is to celebrate the life and achievements of Prof. Arkady S. Lelej, a world-class expert on Hymenoptera, on his 75th birthday. The collection includes a number of papers on systematics, fauna, bionomics and other aspects of studies of extant and extinct Hymenoptera.

Advances in the Systematics of Platygastroidea III synthesizes research on the evolution, systematics, and taxonomy of the third largest superfamily of parasitic Hymenoptera. Taxonomic revisions and descriptions of new species form of the core of the issue, while histological examinations of peculiar morphological features help refine our understanding of character evolution throughout the superfamily.