Dogwood sawfly

Description

Macremphytus testaceus is a large dogwood sawfly. It occurs in the United States and southern Canada from the east coast to the Great Plains. It is most common in the northeast, uncommon in the southeast, and there a just a handful records in the west and in Central and South America.

Adults are wasp-like in appearance but the abdomen is broadly joined to the thorax and they do not sting. Females are ⅜″ to 7⁄16″ (10.0 to 10.8 mm) in length. Males are smaller, averaging 5⁄16″ (8.3 mm) in length.

The head is mostly reddish brown with small areas of black. The plate on the front of the face (clypeus) has a deep circular impression for half or more of its length, and a ridge on the front margin. The antennae are long and are compressed laterally. There are nine segments. The first and second segments and the basal half of the third segment are reddish-brown. The second segment is short, as wide or wider than long. The outer (distal) half of the third segment and the fourth and fifth segments are black. The third segment is as long as or slightly longer than the fourth. The last four segments are white.

The thorax is black, sometimes with a few reddish-brown spots. A small plate over each wing base (tegula) and a plate near the rear margin of the thorax (metascutellum) are whitish. The plate in the middle of the front margin of the thorax (mesoscutum) may be whitish or black.

The abdomen is reddish-brown to dark brown.

The legs are reddish-brown to whitish. The third segment (femur) and fourth segment (tibia) are reddish-brown on the basal half, black on the distal half.

The wings are lightly and uniformly tinted brown. On the forewing the anal crossvein is oblique.

Size

Male: Average 5⁄16″ (8.3 mm)

Female: ⅜″ to 7⁄16″ (10.0 to 10.8 mm)

Similar Species

Dogwood sawfly (Macremphytus tarsatus) is mostly black.

Habitat

Deciduous and mixed forests, yards with ornamental dogwoods.

Ecology

Season

One generation per year. May to July.

Behavior

Life Cycle

Females lay up to 100 or more eggs on the underside of a single dogwood leaf. The eggs hatch in July and feed on the leaf, skeletonizing it. The final instar larva seeks rotted wood, or house siding, to make a cocoon, in which it overwinters. Adults emerge in May and June.

Larva Food/Hosts

Leaves of dogwoods

Adult Food