Dogwood sawfly

Description

Macremphytus tarsatus is a large sawfly. It occurs on 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.

Adults are wasp-like in appearance but the abdomen is broadly joined to the thorax and they do not sting. Females are 7⁄16″ to ½″ (10.8 to 11.8 mm) in length. Males are a little smaller, 7⁄16″ to ½″ (10.8 to 11.8 mm) in length.

The head and body are black. The second section of the thorax is pitted and does not have conspicuous white spots.

The antennae are bicolored and have 9 segments. The first 5 segments (nearest the head) are black. The remaining segments are bright white. The second segment is very short, as wide or wider than long.

The legs are bicolored. The femur and tibia of the two hind legs are black. The femur and tibia of the four other legs may be black or whitish. The tarsi of all legs are white.

The newly hatched larva is translucent yellow. After molting a second time it is covered with a powdery, white, waxy coating that looks like bird droppings. After the final molting they are about 1″ long, have a shiny black head, are yellow below, and are white with a single row of black spots above. The black spots are broad and have a white center.

Size

Male: ⅜″ to 7⁄16″ (9.7 to 10.5 mm)

Female: 7⁄16″ to ½″ (10.8 to 11.8 mm)

Similar Species

Dogwood sawfly (Macremphytus testaceus) is mostly reddish-brown.

Habitat

Deciduous and mixed forests, yards with ornamental dogwoods.

Ecology

Season

Late May to July. One generation.

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 late May to July.

Larva Food/Hosts

Dogwood leaves

Adult Food