614 FIFTH REPORT OF THE ENTOMOLOGICAL COMMI88ION. 
less marked farrows, and with the corresponding interstices convex. 
Surface of gall not shining, lighter or darker brown, speckled with 
small irregalar blackish pustules, and sparsely beset with moderately 
[Ong whitish hairs, which an* easily abraded. Average height of gall. 
.7.V" ! "; diameter, 2 to 3 mm . Cell oblong oval, inclosed by thick, woody 
side walls, but with a thin bottom, and at the roof (/. e., toward the 
apperside of the leaf) covered with a thiu soft layer. Gall on upper 
side of leaf usually visible as a small circular pustule of brownish or 
grayish color. The gall is also at once recognizable from its shape, 
but might readily be mistaken for a Psyllid gall. 
34. Cecidomyidous galls on the under side of the leaf, either singly 
or in smaller or larger numbers, usually between the leaf-veins, rarely 
crossing the large ribs. The gall is a more or less stout conical spine 
arising from a circular base, and either gradually and regularly taper- 
ing toward the tip or more suddenly narrowed a short distance from 
the base, and then with the sides more vertical ; tip more or less acute 
and often slightly curved. Color pale yellowish, surface a little shin- 
ing, either without distinct sculpture or with faint longitudinal fur- 
rows, especially near the base. Average height, 4 mm : average diame- 
ter at base, 2.S mm . The walls of the gall are thin except near the base, 
where they are thicker ; the cell is elongate ovoid, and extends from the 
base to the tip of the spine. On the upper side of the leaf the gall is 
visible as a small circular slightly depressed spot of pale color aud 
furnished in the center with a small nipple. While issuing, the per- 
fect insect pushes off the tip of the spine. 
35. Cecidomyidous galls on the under side of the leaf arising from 
the leaf- veins, either siugly or in groups or in rows, either assuming a 
vertical position or more or less reclining or even horizontally placed. 
Gall cylindrical, or very slightly narrowed at base ; at tip always trun- 
cate with a median nipple. Color pale yellow, surface opaque, faintly 
longitudinally striate aud usually beset with sparse, long, white hairs, 
which, however, are easily lost. Average height of gall, 2.5 mm ; diame- 
ter, 1.2 mm . The walls are thin, the cell elongate with the apical side 
truncate, and the basal end conical. On the upper side of the leaf the 
gall is barely visible as a small yellowish spot on the veins. 
This often occurs in company with the preceding species, of which 
it may possibly be an extreme but constant variety : at least a form 
which combines the characters of the two is not infrequent. It is inter 
mediate in size, short, conical, with truncate tip and either hairy or 
glabrous. 
HACKBERRY PSYLl ID.t. 
The Hackberry is infested by a number of gall-producing Psyllida? 
which are all referable to the genus Pachypsi/Ua Riley (Proc. Biol. 
Soc. Wash., v, 2, 1889, p. 71). The imagos are stout-bodied insects 
with the head vertically deflexed and rugosely punctate: vertex not 
narrowing anteriorly ; frontal cones more or less oval, well separated 
from the vertex and at most half as long as the latter ; antenna? stout. 
