Nature never ceases to amaze and bewilder me. Symphyta (sawflies, horntails, and wood wasps) Hymenoptera (ants, bees, wasps, and sawflies) Uncommon throughout its range, rare in Minnesota Pollen, nectar, honeydew, sap, and other insects. Leaves of mostly black walnut and butternut, but it has also been reported on hickory. One generation per year in Minnesota: July and August This feature gives the species its common name. The body is densely covered with white, cottony or woolly, hair-like processes (flocculence). The head capsule is white with two black eye spots. Late stage larvae are ⅝ ″ to 13⁄ 16 ″ (15 to 21 mm) long. On the front leg the tibia has two spurs at the tip. On the hind leg the end third of the third segment (femur), the end third of the fourth segment (tibia), and the tip of the last section (tarsus), are black.

The second segment (trochanter) has two segments. The basal half of the first segment (coxa) of each leg is black. The legs are long and slender and mostly white. On the male the hindwing does not have a peripheral vein. On the hindwing both the radial sector (R s) cell and the media (M) cell are present. On the forewing, the anal crossvein is oblique. The wings are mostly clear and evenly tinged brown. The female has a saw-like ovipositor at the tip of the abdomen.

The middle thoracic exoskeletal plate (mesoscutellum) is covered with deep, closely spaced punctures. The thorax and abdomen are broadly connected. Segments 7 and 8 are not broadened at the tip. Segments 5 through 9 are reduced in size and are brownish on the underside. The antennae are thread-like, stout, and mostly black. The sensory organs on the upper jaw (labial palpi) and lower jaw (maxillary palpi) are brownish. Males are smaller, ¼ ″ (6.3 to 6.8 mm) long.

Adults feed on pollen, nectar, honeydew, sap, and other insects.įemales are 5 ⁄ 16 ″ (7.7 to 8.4 mm) long. The larva is host-specific, feeding almost exclusively on the leaves of butternut and black walnut, though it has been collected on hickory in the northeast.

It is most common in the northeast, rare in Minnesota. It occurs in the United States east of the Great Plains and in southern Ontario and Quebec.

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