RES Handbook Vol 6 Part 2c. Hymenoptera - Symphyta

OF the three tribes in this subfamily only the Cladiini and Nematini occur in Britain; the Pristolini are, so far as is known, confined to North America. About 750 species a re so far known, in over 30 genera, confined to the northern hemisphere except for a few on the mountains of tropical regions. The treatment in this Hand book is novel, and many of the characters for separating genera are here used for the first time.