Pachypsylla celtidisasterisca Riley (star gallmaker)

This gall is quite characteristic and readily recognized from Riley's (1890) description. Wells (1920) described in detail the morphology of galls collected near Denton, Texas and included in his paper an excellent drawing of one, apparently the only such illustration which has been published.

Gall: Blister-like, somewhat elevated above and below; above with a short central spine 1 to 2 mm in length which is frequently broken off, below with a central projection which, arising from a narrow base spreads out and divides to assume the form of a small flower or star, sometimes the projection does not spread out in the galls found on C. reticulata but instead forms a hollow tube 2 to 3 mm in length. Cells circular, about 4 mm in diameter at the time of gallmaker emergence.

Hosts and Distribution: In Central Texas P. celtidlsasterisca is the most abundant leaf pachypsyllld and this is perhaps true for the state as a whole in which it was found in nearly all areas of collection. This is the only free living species of the Texas blade pachypsyllids which is apparently not host specific for either C. reticulata or C. laevigata. However, in the overlap zone between the two hosts in Central Texas there is a very pronounced host preference for C. laevigata indicating that there are possibly two races of P. celtidisasterisca in Texas. This will be discussed in greater detail in a later section. It was found on trees having major features of C. occidentalis in Oklahoma but as it apparently hasn't been reported from the midwestern and northeastern states it may not extend Into the main part of the range of this hackberry.

Star gall with upper central spine

Pachypsylla celtidisasterisca

Celtis laevigata, reticulata

Galls rounded, raised on the upper side; star-shaped or flower-shaped on the under side

Star gall without upper central spine

Pachypsylla celtidisasterisca

Celtis tenuifolia, (occidentalis) [parentheses indicate occasional observation]

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.

Pachypsylla asteriscus

Star-shaped or flower-shaped leaf gall and not forming a depression on the under side, on the upper surface blisterlike, height 1.25 mm, diameter 5 mm.

Pachypsylla celtidisasterisca Riley, 1890

Pachypsylla celtidis-asteriscus Riley, 1884 [nomen nudum]. Proc. Amer. Assoc. Advan. Sci. 32:319.
Pachypsylla celtidis-asteriscus Riley, 1890. USDA Bull. 7:618.
Pachypsylla celtidisasterisca: Riemann, 1966 [emendation]. Ann. Entomol. Soc. Am. 59:1089.