Phylloxera picta Pergande, n. sp.
The galls of this species resemble very much those of c.-septum, though ordinarily smaller, much more flattened, and to all appearances entirely destitute of a dividing membrane. The insects are also smaller and paler and exhibit some characters which tend to separate it from that species. The transverse diameter of the gall varies between 3-6 mm and the vertical diameter between 2-3 mm. It is quite flat on both sides, though somewhat more elevated and more convex on the upper, with a more or less distinctly depressed ring surrounding the base of the nipple. Both sides of the gall are provided with a short, conical nipple, each closed till maturity, and furnished inside and generally also at the tip with fine pale hairs. The lower nipple always remains closed, while the upper opens in a round or oval mouth, split into several very short, recurved bracts covered with fine pubescence. The walls of this gall are very thin and semi-transparent so that the insects can be seen moving about if held towards the light. The color is variable. Some are quite dark-green with a faint purplish shade and with the nipple and a ring around its base dark red. Others are of the color of the leaf or slightly paler, with a faint purplish ring surrounding them, the nipple and the depression surrounding its base pale buff or pale clay-yellow. Another variety is more or less pink, its margin yellowish or concolorous with the leaf. Still others are pale greenish-yellow with a faint purple ring surrounding the still darker nipple, besides many other variations. The under side is uniformly paler than the leaf and the nipple yellowish.
It occurs on Hicoria tomentosa and matures by the end of May or early June.
To separate this gall from many of the forms of Ph. intermedia is often very difficult, especially after they have burst open, when they resemble each other quite closely, though a comparison of the winged forms of both will show them to be unmistakably good species.
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License:
Public Domain / CC0