Phylloxera caryae-scissa Riley
This gall, as already indicated, bears a close resemblance to that of hemispherica but it will be unsafe to consider them identical until further careful study is made of the latter species.
The first galls of caryae-scissa were received in 1880 from Mr. W. H. Ashmead, of Jacksonville, Fla., found growing upon Hicoria alba. Since then the same species has been occasionally observed in the vicinity of Washington, always growing upon the leaves of Hicoria tomentosa. It is a rather rare species, and occurs for the most part singly.
In general appearance it closely resembles that of Ph. rimosalis, for which it might readily be mistaken, but the upper surface of c.-scissa is never flattened, as in rimosalis, while the orifice is never round or nipple-like, but always a transeverse slit. All the different forms of insects, from the stem-mother to the winged female of c.-scissa, are also larger and darker, with the antennae much longer and more slender, particularly in the winged form.
The transverse diameter of this gall ranges from 8-14 mm and and the height from 2-5 mm or more. It is about equally convex on both sides, though sometimes more prominent either above or beneath, and often with a slight, central, nipple-like projection above. The surface on both sides is more or less distinctly covered with short, fine, yellowish hairs when upon Hicoria tomentosa; while upon H. alba it is smooth above and but slightly hairy beneath. The gall is always situated between two of the transverse veins, with the slit either parallel with them or slightly oblique. When young, this slit is slightly closed and not easily seen, but forms regular, shallow lips, densely pubescent, when older. Color above and beneath pale greenish or dirty yellowish- green.
The winged female may be found from the middle of May to the middle of June.
