Tenthredinidae is the largest family of sawflies, with well over 7,500 species worldwide, divided into 430 genera. Larvae are herbivores and typically feed on the foliage of trees and shrubs, with occasional exceptions that are leaf miners, stem borers, or gall makers. The larvae of externally feeding species resemble small caterpillars. As with all hymenopterans, common sawflies undergo complete metamorphosis. The family has no easily seen diagnostic features, though the combination of five to nine antennal flagellomeres plus a clear separation of the first abdominal tergum from the metapleuron can reliably separate them. These sawflies are often black or brown, and 3 to 20 mm long. Like other sawflies, they lack the slender "wasp-waist", or petiole, between the thorax and abdomen, characteristic of many hymenopterans. The mesosoma and the metasoma are instead broadly joined. The Tenthredinidae are also often somewhat dorsoventrally flattened, which will distinguish them at least from the slender cephids (which, together with the common sawflies, comprise many of the Nearctic species of Symphyta). Females use their saw-like ovipositors to cut slits through barks of twigs, into which translucent eggs are wedged, which damages the trees. They are common in meadows, and in forest glades near rapid streams. Adults eat little, while larvae feed on foliage of streamside trees and shrubs, especially willow. A number of species and genera have been described from the fossil record such as Eriocampa tulameenensis and Pseudosiobla campbelli of British Columbia. Life cycle Cladius difformis Taxonomy The Tenthredinidae are divided into seven subfamilies. Of the 430 genera, nine contain more than 50 species. Subfamilies and genera Subfamilies and genera within this family include: Subfamily Allantinae Adamas Malaise, 1945 Allantus Panzer, 1801 Ametastegia A. Costa, 1882 Apethymus Benson, 1939 Athalia Leach, 1817 Empria Lepeletier, 1828 Eriocampa Hartig, 1837 Monosoma MacGillivray, 1908 Monostegia O. Costa, 1859 Taxonus Hartig, 1837 Subfamily Blennocampinae Ardis Konow, 1886 Blennocampa Hartig, 1837 Cladardis Benson, 1952 Claremontia Rohwer, 1909 Eutomostethus Enslin, 1914 Halidamia Benson, 1939 Hoplocampoides Enslin, 1913 Monardis Benson, 1952 Monophadnoides Ashmead, 1898 Monophadnus Hartig, 1837 Paracharactus MacGillivray, 1908 Periclista Konow, 1886 Phymatocera Dahlbom, 1835 Rhadinoceraea Konow, 1886 Stethomostus Benson, 1939 Tomostethus Konow, 1886 Subfamily Heterarthrinae Caliroa O. Costa, 1859 Endelomyia Ashmead, 1898 Fenella Westwood, 1840 Fenusa Leach, 11817 Heterarthrus Stephens, 1835 Messa Leach, 1817 Metallus Forbes, 1885 Parna Benson, 1936 Profenusa MacGillivray, 1914 Rocalia Takeuchi, 1952 Scolioneura Konow, 1890 Subfamily Nematinae Amauronematus Konow, 1890 Anoplonyx Marlatt, 1896 Cladius Illiger,