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Genus Pachypsylla - Hackberry Psyllids

Hackberry Psyllid - Pachypsylla celtidisasterisca hackberry blister gall, Pachypsylla celtidisvesiculum - Pachypsylla celtidisvesicula psyllid..? - Pachypsylla Psyllid with larval erythraeid mite - Pachypsylla Hackberry leaf gall - Pachypsylla Pachypsylla Pachypsylla Psylloidea  - Pachypsylla
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies)
Suborder Sternorrhyncha (Plant-parasitic Hemipterans)
Superfamily Psylloidea
Family Carsidaridae
Subfamily Pachypsyllinae
Genus Pachypsylla (Hackberry Psyllids)
Explanation of Names
Pachypsylla Riley 1885
Between 7-13 spp. in our area (1), 8-14 total(2) (see remarks)
2-6mm (3)
Key to species, adapted from Tuthill, 1943 (3)
1a. Head and thorax pubescent, not shining; marginal cells of forewing very elongate; forming galls on leaves or leaf petioles ... 2
1b. Head and thorax glabrous, marginal cells not elongate; forming galls on buds or twigs ... 3
2a. Large species (>5mm), wings rhomboidal, forming galls on leaf petioles: Pachypsylla venusta

2b. Smaller species (typically between 2-4mm), forming galls of various types on leaves ... Pachypsylla celtidismamma complex (includes P. celtidismamma, P. celtidisvesicula, P. celtidisasterisca, P. celtidisumbilicus, and P. cohabitans. See remarks below)

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

3b. Forewings maculate ... 5
4a. Branches of medial cell sinuate, forming galls beneath bark on twigs: Pachypsylla celtidisinteneris

4b. Branches of medial cell not sinuate ... 6
5a. Forewings finely mottled apically (galls are unknown): Pachypsylla dubia
5b. Forewings with large maculae, forming pubescent galls on axillary buds: Pachypsylla pallida
Throughout North America, especially in the east (2)
Celtis (Hackberry)
Life Cycle
Gall, nymphs, adult
With our current knowledge, adults belonging to the Pachypsylla celtidismamma complex are indistinguishable from each other, though the galls themselves 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).
Internet References
hackberry nipplegall maker (P. celtidismamma): 1 | 2
hackberry blistergall psyllid (P. celtidisvesiculum): 1 | 2
Works Cited
1.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
2.Ouvrard D. (2013) Psyl'list - The World Psylloidea Database
3.The psyllids of America North of Mexico: (Psyllidae: Homoptera) (Subfamilies Psyllinae and Triozinae)
Tuthill, L.D. . 1943. Iowa State College Journal of Science 17: 443-660.
4.Biosystematics of hackberry psyllids (Pachypsylla) and the evolution of gall and lerp formation in psyllids
Yang, M.-M. & C. Mitter. 1993. The Ecology and Evolution of Gall-forming Insects. United States Dept. of Agriculture.
5.The Authority and Types for the Hackberry Gall Psyllid Genus Pachypsylla (Riley) (Hemiptera: Psyllidae)
Thomas, D.B. 2011. Entomological News, 122(3):279-287.