the wing, and reaches the costal vein about seven-eighths of the length of the wings. (2 and 3.) The lower main branches form the upper and lower main branches of the cubitus, which branches directly from the primary stalk at B. The upper main branch of the cubitus divides again at C, but neither branch is a continuation of the main branch. The lower main branch of the cubitus divides at N, a longer and convex branch reaches the margin at K, and a shorter branch reaches the margin at L.

Running from the primary stalk to the lower margin of the wing is an indistinct vein (AM) called the “clavus.” In the areas between the branches of the cubitus—namely, DE, EK, KL—are three small triangular markings, composed of very small dots; on the veins of the wing are some very short fine hairs.

The hind wing (Plate XXXIII., fig. 2) is larger in comparison with the fore wing than in either Trioza panacis or Trioza pellucida. The veins are only marked by rows of large dots, and the whole wing is covered with very small dots. The rostrum is pointed and blackened at the tip, ending in the male with three setæ (Plate XXXIII., fig. 9), which are entirely absent in the female.

Length, about 2·25 mm.

Pupa.—Head generally depressed behind. Eyes large, and of a very dark brown colour. Ocelli three, situated as in the adult. The fringe is very strongly developed, but the individual rods are longer and closer together than in T. Panacis or T. pellucida, and the cups are more or less simply thickenings of the lower portions (Plate XXXIV., fig. 2). The anal ring is ventral, and closely resembles that of Trioza panacis.

Length, about 1·75 mm.

Hab. I have found it on Pittosporum tenuifolium, where the pupæ lie in little pits both on the ventral and dorsal surfaces of the leaf. Its presence is indicated by the presence of large quantities of a white semi - transparent excretion termed “manna,” which fills up the hollows of the leaves, and in windy weather falls to the ground, giving the appearance of a light fall of snow.

Adult Female.—Generally of a light-yellow colour, with a slight green tint which becomes darker during life, probably due to the green food showing through the semi-transparent skin. Head and thorax not so green as the abdomen. Genitalia are of a dark-brown colour, especially at the tips. The length, including genitalia, about 2·25 mm., and expanse of wings 7 mm. At the posterior and ventral surface of the thorax is a short blunt projection (Plate XXXIII., fig. 7, G), found also in the male, but its function seems to be unknown.

The head is broader than long, concave in front and depressed behind. The lower and front portion is prolonged into two conical projections, with numerous hairs. The rostrum is situated on the ventral surface of the thorax, and has a black pointed tip. The female has no setæ on the rostrum. Wings are large and membranous, and arch over and extend beyond the abdomen. Antennæ of ten joints (Plate XXXIII., fig. 8), the third joint being no thicker than the fourth. The first two joints are short, round, and scaly; third joint is longest; last joint is dilated and of a dark colour, with two unequal spines on its extremity. Legs are slender; tibia has numerous small spines on distal end, but in the third pair of legs these are partly replaced by four black conical projections. Tarsus is double-jointed, the second joint having two hooks or spines and a sucker on its distal end. Abdomen has a conspicuous yellow mass (Plate XXXIII., figs. 6, 7), probably corresponding to the pseudovitellus^* of the pupa. The anus is situated on the dorsal surface some distance in front of the genital organs. The genitalia are larger in comparison with the abdomen than in Psylla pyricola, and are of a dark-brown colour, especially at the tips. Genitalia consist of three plates (Plate XXXIII., fig. 6)—the upper genital plate (A), the lower genital plate (D), and, close to the upper genital plate, a third plate (Plate XXXIII., fig. 6, B) called by Witlaczil the “main rod.” Between this and the lower genital plate is a very transparent roundish lobe called the egg-sheath (C).^† Viewed sideways the upper genital plate is longer than the lower; all except the egg-sheath are sharply pointed, with numerous hairs scattered about.

Adult Male.—This is very similar to the female, but the rostrum has three setæ, which are entirely absent in the female. The anus (Plate XXXIII., fig. 7, H) is situated on top of the upper genital plate instead of on the abdomen itself, as in the female. Genitalia (Plate XXXIII., fig. 7): The lower genital plate (B) is large and round; and forms the end of the body. It is prolonged upwards to form a pair of claspers (C). The upper genital plate is about as broad as it is long, and, like the remainder of genital organs, stands up almost at right angles from the body. Penis (E) is long and doubled back on itself at D, and provided with a hook at the end. Running through the penis is a duct (K). Having mounted two specimens during copulation, I find the arrangements of the organs are as follows: The claspers of the male grasp the lower plate of the female; the upper plate of the male clasps the upper