boring in the forks of the young wood. If discovered in time it can, to a great extent, be gotten rid of by shaking the trees both night and morning. The Polycaon is not a very dangerous pest, although, it causes more or less injury to the tree, which may result in the loss of several of the minor branches.
PSYLLA OLEÆ.
(See Plate XI.)
The egg of the psylla is spheroidal in shape, and of a diaphanous white color, a little over a hundredth of an inch in diameter. (Fig. 2.)
The larva (Fig. 3) is a depressed ovoid, oblong, the head bi-festooned in front, the last abdominal ring is very much larger than the others. It is rather soft and of a greenish white color, the eyes red, the extremities of the antennæ and tarsi, black. It is completely covered with a cottony substance which is thick and long on the abdomen, and falls behind in a fringe.
The chrysalis (Fig. 4) resembles the larva in its general appearance, differing from it in the shield wing, which is oval and ridged, covering the sides of the abdomen, greenish in color, with last abdominal ring brown or nearly black, the shield wing of a yellow brown color. The insect (Fig. 5, 6) has a wide head, triangular in shape, the upper part curved in, and square at the corners, with a deep scallop nearly bi-secting the lower part, the eyes oval, placed at upper corners of the head, the antennæ (Fig. 8) six jointed; the last one terminating in two short bristles, the upper thorax very short, the lower thorax large, convex, twice as long as it is wide, and nearly hexagonal. Upper wings or shield wing, oval, rhomboidal, much longer than the abdomen and meeting in a sort of roof at the upper margin of the skull; a sinew, starting from the point of the shoulder, is visible, which bi-sects it. The lower wings are shorter than the upper ones. Abdomen small terminating in a blunt point, and in the female provided with a distinct
