The Cephoidea are a small superfamily within the Symphyta, containing some 100 species in a single family, Cephidae, commonly referred to as stem sawflies. Most species occur in the Northern Hemisphere, especially in Eurasia

Eurasia

Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

. The larvae are stem borers in various plants, especially grass

Grass

Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

es, but sometimes other herbaceous

Herbaceous

A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...

 plants, shrubs, or trees. A few are pests of cereal

Cereal

Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...

 grains (e.g. Cephus cinctus, which attacks wheat

Wheat

Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

). They are exceptionally slender for Symphytans, often resembling other types of wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, and they are the only Symphyta which lack cenchri

Cenchrus (insect)

The cenchrus is a specialized anatomical structure in the insect group known as sawflies. The cenchri are small blister-like lobes on the metanotum of these insects, just posterior to the mesothoracic scutellum, shaped and positioned in such a way as to latch onto the base of the front wings when...

. They are sometimes postulated to be the sister taxon to the Apocrita

Apocrita

Apocrita is a suborder of insects in the order Hymenoptera.Apocrita includes wasps, bees and ants, and consists of many families. It includes the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" formed between the first two segments of the actual abdomen; the...

, though the Orussidae

Orussidae

The family Orussidae is the only Symphytan group which is parasitic, thus giving them the common name parasitic wood wasps...

are more commonly considered such.