HACKBERRY GALLS. 613 
a large egg of some diurnal Lepidopteron ; short, conical, or subglobu- 
lar in outline, arising from a circular, truncate base, rounded off at tip 
where it is furnished with a short spine or nipple; surface dark green, 
opaque, granulose, usually with faint and shallow longitudinal furrows 
and usually hirsute with short stout hairs ; sides at the base with more 
or less distiuct, irregular protuberances. The gall is not entirely sessile, 
but only connected with the twig at the central part of its base. A 
vertical section shows a single spherical cell (rarely two) having a 
thick whitish yellow, hard and woody wall. Average height of gall 4 mm 
(excluding the apical spine) ; average diameter at base 3.4™ m . The gall 
varies in shape, some specimens being more conical, others nearly glob- 
ular or even slightly depressed at tip, while others are not hairy and 
less opaque, the surface being covered with little pustules. The latter 
form possibly constitutes a distinct species. 
31. Cecidomyidous galls on the tender twigs occurring either singly 
or in groups of two, three, four or more specimens ; rarely, also, singly on 
the under side or even the upper side of the leaf. The gall bears a close 
resemblance to the winged seed-capsule (achenium) of a Rumex, but the 
wings vary in number from three to five and are often irregularly devel- 
oped, while the tip always ends in a long curved spine. The wings termi- 
nate in a sharp ridge which is sometimes double. Gall opaque, not 
hairy, sculpture consisting of faint and irregular transverse striae ; color 
pale yellowish-green, at apical third usually of a more decided green 
and darker. A longitudinal section reveals a single large, regularly 
ovoid cell surrounded by a thin hard wall. Average height of gall 4.5 mm , 
excluding the apical spine ; generally as wide as high ; length of apical 
spine variable, but usually a little more than half the height of the gall. 
This gall is easily recognized from its peculiar form. 
32. Cecidomyidous galls on the under side of the leaf, always arising 
from one of the principal leaf- veins, occurring usually singly, rarely in 
pairs. In form, sculpture, and pubescence the gall bears a most strik- 
ing resemblance to that produced by Pachypsylla ccltidis-pubescens (see 
p. 619) but it is much larger, more globular, and at once distinguished by 
the absence of the cupuliform depression on the upper side of the leaf 
which is so characteristic of many Pachypsylla galls. A vertical cut 
through the gall shows a relatively small ovoid cell surrounded by a 
thick, hard yellowish-white wall. On detaching the gall the base is seen 
to be truncate and attached to the rib of the leaf by an extremely short 
conical style which is not visible from the sides. Average height 3.5 mm ; 
diameter at middle, 3.5 mm to 4 mm . 
33. Cecidomyidous galls on the under side of the leaf arising from the 
leaf-ribs, occurring either singly or in smaller or larger groups. Gall 
rosette-shaped, resembling the seed-capsule of certain Malvaceous 
plants of the genus Hibiscus, circular in outline, greatly flattened on 
the top and here furnished with a short central spine or median nipple 
(frequently broken off); sides sulcate, with from ten to twelve more or 
