Pachypsylla

Pachypsylla is a genus of psyllids. Species of the genus Pachypsylla lay eggs on the leaves of the Celtis occidentalis tree. Upon hatching, the young psyllids become encased in a gall which the young leaf parts grow in response to the infestation.

Species
The following species are recognised in the genus Pachypsylla:
 * Pachypsylla celtidisasterisca Riley, 1890
 * Pachypsylla celtidiscucurbita Riley, 1890
 * Pachypsylla celtidisgemma Riley, 1885 – hackberry bud gall maker
 * Pachypsylla celtidisglobula Riley, 1890
 * Pachypsylla celtidisinteneris Mally, 1894
 * Pachypsylla celtidismamma (Riley, 1881) – hackberry nipplegall maker
 * Pachypsylla celtidispubescens Riley, 1890
 * Pachypsylla celtidisumbilicus Riley, 1890
 * Pachypsylla celtidisvesicula Riley, 1890 – hackberry blistergall psyllid
 * Pachypsylla cohabitans Yang & Riemann, 2001
 * Pachypsylla dubia Patch, 1912
 * Pachypsylla pallida Patch, 1912
 * Pachypsylla tropicala Caldwell, 1944
 * Pachypsylla venusta (Osten-Sacken, 1861) – petiolegall psyllid