Pachypsylla celtidis-asteriscus n. sp.

This gall, on the upper side of the leaf, is very similar to the foregoing species, i.e., represented only by a barely raised, blister-like spot, distinguished from the surface of the leaf mainly by its lighter color but furnished in the middle with a moderately long spine which is sometimes clavate but readily broken off and often lost when the galls attain maturity or in dried specimens. In this case there is a more or less conspicuous nipple left in the center of the gall. The gall is normally circular in outline, but often irregular and limited by the leaf-nervules. Average diameter, 5mm.; sculpture coarser than, but of the same nature as, that of the leaf. On the under side of leaf it is barely distinguishable as a slightly discolored spot, but the center rises from a thin base and, spreading out, assumes the form of a small flower (resembling somewhat that of a Convolvulus) or a star, and this resemblance to a flower is increased by the presence of a small, rounded, median nipple, which is often surrounded by a circular rim. Average height of this flower shaped excrescence, 1.25mm; diameter at top, 2.50mm. The walls of these galls are a little thicker than the leaf itself, and, as in the preceding species, the cell is a low chamber with a straight roof (i.e., toward the upper surface of the leaf) and the bottom a little convex. The mature pupa makes its way out through an oval slit always on one side of the roof of the gall.

- CV Riley: (1890) Insects injurious to the hackberry^©

Reference: https://www.biodiversitylibrary.org/item/42358#page/632/mode/1up