614 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



less marked farrows, aud with the corresponding interstices convex. 

 Surface of gall not shining, lighter or darker brown, speckled with 

 small irregulai" blackish pustules, and sparsely beset with moderately 

 long whitish hairs, which are easily abraded. Average height of gall. 

 75mm. diameter, 2 to 3"^™. Cell oblong oval, inclosed by thick, woody 

 side walls, but with a thin bottom, and at the roof (i. e., toward the 

 upper side of the leaf) covered with a thin 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, aud 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""" ; average diame- 

 ter at base, 2.8™"\ 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 and 

 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 singly 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 and usually beset with sparse, long, white hairs, 

 which, however, are easily lost. Average height of gall, 2.5™™ ; diame- 

 ter, 1.2™"". 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. 



HaCKBERHY PSYLl ID^. 



The Hackberry is infested by a number of gall-producing Psyllidfe 

 which are all referable to the genus Fachypsylld 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 ; antennae stout. 



