common sawflies

Craterocercus is a small genus of common sawflies. There are just six species worldwide, and all of them occur in North America. Five species occur north of Mexico. Three species occur only in the east, two occur only in the west. One species has been recorded near Minnesota and may eventually be found in the state (CCESR). There are only two records from Minnesota, but those have not been identified beyond the genus level.

All Craterocercus larvae feed externally on oak leaves.

Craterocercus are small sawflies. Adults are ¼″ to ⅜″ (6 to 9 mm) in length. The body is long, cylindrical, and mostly black, with white, yellow, or red markings.

There are two large eyes on the sides of the head and three small simple eyes (ocelli) in a triangle on top of the head. The antennae are thread-like (filiform) but stocky. They have 9 segments and are the same thickness throughout. The second segment (pedicel) is wider than it is long. The third segment is only slightly longer than the fourth. The remaining segments get progressively shorter. The plate on the face (clypeus) has a deep, broad, semicircular indentation on the lower margin. The jaws (mandibles) are symmetrical, with the same number and size of teeth on each. On each side of the face, the area between the compound eye and the mandible (malar space) is narrow, less than the diameter of the front ocellus.

On each side of the thorax there is a small plate (mesepimeron) in the shoulder area. The front portion of the mesepimeron has several hairs (setae).

The wings are clear. On the forewing, veins 2A and 3A curve upward and meet vein 1A, creating a small basal anal cell. The radial crossvein (2r) is present. Veins M and Rs+M are widely separated where they meet vein R. On the hindwing, vein 2A meets vein 1A. Cells RS and M are present. The basal anal cell is also present.

The last part of each leg (tarsus), corresponding to the foot, has five segments. The last tarsal segment has a pair of claws at the tip. Each claw has a short tooth on the inner surface near the center.

Sources

24, 29, 30, 82, 83.

No species in this genus has a common name, nor does the genus itself. The common name for the family Tenthredinidae is common sawflies, and it is applied here for convenience.

Location: Woodbury, MN