Hackberry Blister Gall Psyllid

Galls are blister-like, most prominent on the upper surface of the leaf . Adults are similar to P. celtidismamma but are smaller and with wing pattern usually more diffuse. Tuthill notes that the sudden narrowing midway of the ventral valve of the female genital segment is the most reliable way to distinguish the two species . See also Zack Falin's comment below. Zack Falin on P. celtidismamma and P. celtidisvesicula : While the galls may be easy to distinguish, these two species are a real pain. A lot has been published on these, but here are my observations: given Crawford's key, I'm calling the individuals 2.5 mm and smaller P. celtidisvesicula and those larger than 3.0 mm P. celtidismamma . The individuals in between (about a third of my specimens)- I don't know! The smaller ones tend to be darker with less pronounced maculations on the head and thorax with slightly more consistent wing patterns. The larger ones tend to have more pronounced maculations on the body and have quite variable wing patterns. They both seem to occur in the same places at the same time, so take this with a grain of salt. There are a number of additional valid species (see Thomas, B. 2011. The authority and types for the hackberry gall psyllid... Ent. News 122: 279-287) that probably fall into this continuum. People are obviously interested in the genetics of these things- that's likely the only way to sort them all out for sure...