Genus Pachypsylla - Hackberry Psyllids

Pachypsylla Riley 1885

Between 7-13 spp. in our area(1), 8-14 total(2) (see remarks)

2-6 mm(3)

Key to species adapted from (3)

1. Head and thorax pubescent, not shining; marginal cells of forewing very elongate; forming galls on leaves or leaf petioles ... 2

2. Large species (>5mm), wings rhomboidal, forming galls on leaf petioles: P. venusta

3. Forewings uniformly brown, forming glabrous galls on axillary buds: P. celtidisgemma

4. Branches of medial cell sinuate, forming galls beneath bark on twigs: P. celtidisinteneris

5. Forewings finely mottled apically (galls are unknown): P. dubia

Throughout North America, mostly eastern(2)

host: Celtis (Hackberry)

Gall -- nymphs -- adult

Within the Pachypsylla celtidismamma complex, adults are indistinguishable, yet the galls are distinct. Historically, most authors have treated all leaf-gallers other than the blister-galler as synonyms of a single species, P. celtidismamma. However, allozyme frequency testing and electrophoretic analysis suggests that there may be up to seven cryptic leaf-galling species, including an inquiline species; further genetic testing may eventually reveal the extent of species boundaries within this group(4)(5).