Sawflies are among the most difficult insects to identify. Actually there are not that many biologists that research this group. So it is a hell of a job getting a specimen correctly identified. Take the animal on this page for instance. It belongs to the genus Dolerus. In the Benelux there are some 30 species within this genus and many of them are entirely black. World wide this is an extremely complicated genus, comprised of some 200 species, including some intricate species complexes. Experts tell the species apart by examining the females saw or the males genitals. Usually a microscope is needed to see the minute differences. We did not kill our specimen, so nobody had any chance of examining the animal on this page under a microscope. Meaning we will never know the exact species. Most Dolerus species fly in early spring (April and May). They do not fly very well and rather slowly and look a lot like the numerous Fever Flies one sees in spring also. The larvae feed on grasses.