Phylloxera conica Shimer.
Dactylosphaera conicum Shimer.
Phylloxera c.-conica Riley.
It is rather strange that Shimer failed to mention the color of this gall, notwithstanding it is one of the handsomest of this group. There can scarcely be any doubt, however, that the gall here considered is identical with that described by him under the above name.
The first notes upon the species were made in 1872 when it was found in Missouri on the leaves of the Bitter-nut Hickory, (Hicoria amara [Carya cordiformis]). This is one of the most widespread and common of the Hickory galls in the Mississippi Valley, and was frequently sent by correspondents for identification. The galls begin to form the latter part of May and are then almost globular, though somewhat more prominent above than beneath, with a scarcely noticeable nipple on the under side, densely covered with yellowish pubescence. Their color is a deep purplish -brown, contrasting prettily with the light green color of the young leaves ; their surface above and beneath is more or less roughened or granulated, and the appearance reminding one strongly of the galls of Cecidomya q.-pilulae of the oak.
By the first week in June the galls are fully grown, but only contain the stem-mother, her eggs and larvae. By the middle of the month the winged female prevails, with but few pupae and still fewer larvae, while in many cases the galls have opened and migration has actively begun. The transverse diameter of the matured gall varies from 3-7 mm and their vertical diameter from 2-5 mm. Many of them are almost globular, and, as a rule, more prominent above than beneath. Occasionally, however, they are more prominent beneath. In the majority, especially the larger galls, the under side is considerably sunken beneath the surface of the leaf and much less conical and usually much paler than when younger. The color above is a dull, dark purplish brown, sometimes, how- ever, with only a brownish shade, or entirely of a dull greenish- yellow. The surface above, and sometimes slightly beneath, is densely and quite coarsely rugose and more or less distinctly pubescent, especially beneath, and covered with a more or less noticeable sticky or viscid excretion. The orifice is more densely pubescent than the rest of the gall, and splits, when mature, into 4-8 short bracts. The walls of the galls are rather stout, leathery and flexible. At full growth the inside is almost pure white, but by the time the insects are ready to leave, the color is brown all through. Generally these galls grow singly, though there are often as many as ten, of which several may be confluent, on the same leaf.
