The American Oak Phylloxera (Phylloxera Rileyi).—There are several described and undescribed species of Phylloxera in this country, most of them inhabiting leaf-galls made on our different hickories. The species herewith figured is the only external feeder known in America, and it is briefly alluded to in this connection to show that, as with the grape Phylloxera, it does not need a "winter egg" to enable it to hibernate, but passes the winter in the larva state (as at Fig. 9),
| Fig. 9. | Fig. 10. | |
| ||
| Phylloxera Rileyi.—a, pupa; b, winged female; c, antenna greatly enlarged; d, portion of infested leaf. | Phylloxera Rileyi.—a, b, dorsal and ventral views of larva as seen hibernating; c, d, highly-magnified leg and antenna of same. | |
firmly attached to the tender bark of the younger twigs, and thus braving all the vicissitudes and inclemencies of that season. In the summer it is found on the underside of the leaves of our white and post oaks, fixed in the centre of a yellowish spot caused by its puncture, and showing most on the upper surface, so that on a badly-infested tree the leaves all look speckled, and seared, and withered. It presents all the different forms and the same biological characteristics that I have described and detailed of the grape Phylloxera.
CONCLUSION.
We have, in the history of the grape Phylloxera, the singular spectacle of an indigenous American insect being studied, and its workings understood in a foreign land, before its presence in its most injurious form was even suspected in its native home. The Franco-Prussian War, with all its fearful consequences to France, has passed away; the five milliard francs (one thousand million dollars) have been paid, as indemnity to her victors, in so short a time that the civilized world looked on in wonder and astonishment. Yet this little Phylloxera, sent out, doubtless, in small numbers, by some American nurseryman, a few years since, continues its devastating work, and costs that unfortunate country millions of francs annually. The last German has been removed from French soil—at terrible cost, it is true—but the Phylloxera army remains; and, if another five milliard francs
