106 



THE OLIVE 



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 OLEiE. 



(See Plate XL) 



The egg of the psylla is spheroidal in shape, and of a diaphan- 

 ous 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-fes- 

 tooned 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 antennae and tarsi, black. It is com- 

 pletely 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 appear- 

 ance, differing from it in the shield wing, which is oval and ridged, 

 covering the sides of the abdomen, greenish in color, with last ab- 

 dominal ring brown or nearly black, the shield wing of a yellow 

 brown color. The insect (Fig. o, 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 antennae (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, rhom- 

 boidal, 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 terminat- 

 ing in a blunt point, and in the female provided with a distinct 



