Please refer also to the following links for details on this group:
Tenthredinidae = Link 1
The predaceous habit has developed in adults of a number of species (Clausen 1940/1962). Adults of Tenthredella nigropicta Smith feed extensively on the larvae and pupae of chrysomelid beetles of genera Melasoma and Plagiodera in Japan, eating 2-3 full grown larvae daily (K. Iwata cited by Clausen, 1940). Hobby (1932) listed different species and their prey in England, including Tenthredo, Tenthredella, and Rhogogaster, their prey comprised mainly of small Diptera and sawflies. Flies that frequent flowers seem favored, probably because of an ease of capture during feeding. Species in genera Macrophya, Tenthredopsis, and Taxonus have also been observed to be predaceous. In most cases only females are predatory.