Pachypsylla celtidiscucurbita n. sp.

This gall, on the upper side of the leaf, forms a cup shaped impression, deeper than in P. c.-mamma., but less deep and with the walls less vertical than in P. c.-globulus ; the cavity is also not widened internally. The outer rim is not sharply limited and not elevated except in one specimen, where it is thickened and bulging as in P. c.-pubescens. The walls and the bottom of the cup are not distinctly sculptured and of a greenish-yellow color (in dried specimens), the rim being reddish yellow and rugose. Average diameter, 1.75 mm.

On the under side of the leaf it arises from a rather slender, but not stylate, base and widens gradually to the middle, thence gradually narrowing toward apex. When viewed from the side the outline of the gall is therefore oval, but the top is always truncate. The sides near the top are furnished with short ribs, which are separated from each other by wide shallow depressions; the apex is formed by an acute rim, which surrounds a cup-shaped depression varying in size and depth according to specimens. Surface neither pubescent nor shining, but finely and indistinctly strigose. Color (dried specimen) rather bright yellow, brownish near center. Average height of gall, 4 mm; diameter, 3.3 mm. Cell as in P. c.mamma, the bottom wall at center much less thick than at sides.

Pachypsylla celtidis-cucurbita var. ?

Gall as seen on the upper side of leaf either as in P. c.-cucurbita, or more often as in P. c.-globulus, i. e., the impression is vertical and widening internally, but the upper rim is either barely or not at all elevated. On the under side of the leaf it is always sessile, not oval in outline, but depressed and button- shaped ; the disk being greatly flattened and with a shallow depression having a small central nipple and surrounded by two concentrical rims, the inner one often obsolete, the outer one rarely so. The sides of the gall have either faint longitudinal furrows or are irregularly rugose. Size very variable ; average height, 1.75 mm; width, 3 mm.

Whether or not this form is specifically distinct from the typical P. c.-cucurbita can not yet be decided. Of the latter I have not many specimens, all from Missouri; while of the variety I have numerous specimens from Missouri and Texas. No specimens strictly intermediate have yet been found.

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

Reference: https://www.biodiversitylibrary.org/item/42358#page/635/mode/1up