I have examined before being laid are without this depression. They are laid side by side in a more or less vertical manner, the blunt end resting on the surface of the water, the pointed end being uppermost, and form rows both transversely and longitudinally, the longitudinal rows varying in number from 6 to 10. The eggs in the median rows are vertical, while the greater diameter of the lower blunt end of the individual eggs causes those of the lateral rows to tilt, so that the lower surface of the raft is wider across than the upper.

The individual eggs (Fig. 35) are cigar-shaped, i.e. thick and rounded at one end, tapering to a point at the other. They are 8 mm. long and .175 mm. across the wider end. The micropyle is at the wide end, and lies within and protected by a saucer-shaped cap. The rim of the cap is densely fringed with delicate hairs. The area around the micropyle has a reticulated appearance. In dehiscence the end of the cap falls back on a hinge (Fig. 36), the larva emerging head downwards.

When first laid the eggs are milky white, but change to a darker colour soon after exposure to the light and air, generally assuming a light brown shade; when found in situ they appear almost black, and when lifted from the water the under-surface appears silvery-white, on account of the film of air mentioned above.

The eggs are firmly held together in the raft, and I have shaken them violently in water without separating them. The rafts drift together and form stars, triangles or rows, the latter lining the water's edge like a row of canoes. They also adhere to the sides of water containers, pieces of drifting debris, blades of grass, Lemna (chickweed), Nasturtium (water-cress) and other weeds. They will withstand a considerable degree of dessication. A raft adhering to the side of a jar, from which the water had receded, was kept dry for 14 days, and on being placed in water hatched in 72 hours.

Culex pervigilans lays eggs all the year round in Auckland, and thousands of recently deposited rafts have been taken from water at 42° F. in country areas. The rafts can be found in every type of breeding place, i.e. slow-running creeks clean or dirty, drains, street gully traps, liquid manure barrels, drains around commercial premises, roof gutters, tarpaulins in railway yards, fire buckets on railway platforms, and in buildings, drinking vessels in fowl yards, stable drains, latrines, flower vases in cemeteries, pickle bottles, and tins on porches of houses, copper and wash tubs in wash-houses, old tyres, iron waggons, disused cars, conservatory water containers, flower pots in houses, and on rockeries, old boots in dumps, enemy guns in the Domain, puddles in the wheel ruts, neglected water tables, lakes, lagoons, tanks, both in the open and in the native bush. On one occasion they were obtained in brackish water with an approximate ratio of one part of fresh water to four parts of sea water, this being in a tidal mangrove swamp at Clevedon in the month of June. For preference the female will lay eggs in water rich in organic matter, but I have found them in water ranging from clean tank water to liquid manure, and again in old boilers where salammoniac had been largely used. The eggs are usually laid between the hours of midnight and daylight, the favourite hour being the one preceding day-

light; on only one occasion have I seen a mosquito depositing eggs in daylight, viz., at 7.45 a.m.

The process of hatching is sometimes a remarkable sight. On one occasion I observed the simultaneous emergence of all the larvae of one raft. First one of the caps at the lower end of the eggs fell away, followed almost immediately by nearly all the others, and for five minutes the lower surface of the raft was a struggling mass of larvae pushing downward, head first from the openings uncovered by the egg-caps. There were 256 eggs in this raft and from these 240 larvae emerged successfully, 7 failed to extricate themselves, and 9 eggs failed to open.

Larva: This larva is easily distinguished from that of the other species described by the long straight siphon (Fig. 37), most nearly resembling in this character Culex fatigans, which has a siphon relatively shorter, more tapered, and wider at the base, especially at the proximal two-thirds. The length of larvae in the fourth instar is about 8 mm. without the siphon. Greater variation is to be found

Fig. 37.—Siphon of larva of C. pervigilans.

in the colouration of this larva than in the other two species described in this paper. They vary from black to brown and from green to greenish-blue; in old rusty containers they are ferruginous and in clean tank water almost white. The wriggling motion is almost straight.

The head (Fig. 38) is of a light golden colour; it is transversely elliptical, being full at the posterior margins. The front margin is slightly arcuate; a deep notch at the insertion of the antennae; maculation of the vertex is slight and is composed of small diamond-shaped spots anteriorly above the base of the antennae, and towards the centre. The mouth brushes are simple and of a golden brown colour. Pre-clypeal hairs short, stout, pointed and turned towards the middle; Pre-antennals absent. Two outer post-antennals 6 to 8 branched, spinose, reaching to proximal third of the antennae; 2 inner post-antennals 4-branched, spinose, reaching in length almost to the anterior margin. Behind the post-antennals are a pair of 4-branched spinose setae. Two pre-ocular bifid hairs equidistant between the eye and antennae. One post-ocular bifid hair. Vertical and trans-sutural hairs can best be noted by reference to the figure. Eyes large circular, usually arcuate posteriorly.

Fig. 38.—Head of larva of C. pervigilans.
Fig. 39.—Antennae of larva.

Antennae (Fig. 39) movable, often seen lying across the front of the head, darker in colour than the head, base black, slightly bent. Situated on the internal two-thirds is a bunch of 16 to 20 finely spinose hairs, in the shape of a fan in length approximately half the length of the antenna. Situated on an offset posterior to the apex are two strong hairs half the length of the narrow distal portion, on the lateral margin of the apex are two more strong hairs, longer than but otherwise similar to those just mentioned; these are movable at will; situated internally between these two sets of hairs is a short strong thick transparent spine. The surface and margins of the antennae are covered with short appressed spines, darker in colour than the antennae.

Mentum (Fig. 40) index 3.2: 2.8: pentagonal in form, 6 to 7 strongly incurved pointed teeth on each side, one large central tooth at the apex; the lower surface has a deeply arched concave depression. Mandible (Fig. 41) quadrangular, two long incurved spines below the collar on the inner margin, one short stumpy spine below these; a row of long hairs arises from the collar; four to five teeth on the process, anterior one very large, also one long pointed tooth above, a process below with moderately long hairs. Maxilla (Fig. 42) conical, divided by a wide median suture; along the suture is a series of shortened hairs; at the apex is a series of fine hairs. Inner margin carries a series of strong stiff bristles.

Fig. 40.—Mentum of larva of C. pervigilans.
Fig. 41.—Mandible of larva. Fig. 42.—Maxillae of larva.

Thorax seen from above (Fig. 43) slightly wider than head, wider than long, divided into three angulations, with two sets of 4-branched hairs on pedunculate stems, which spring from a strong chitinous papilla, hairs black, very minutely spinose; on the anterior margin are four single, bifid, and trifid branched setae, arising from

Fig. 43.—Dorsal view of thorax.
Fig. 44.—Ventral view of thorax.

small papillae; these hairs extend in length to beyond the anterior margin; several single and bifid hairs are to be seen on the dorsal surface. Ventral chaetotaxy can be seen by reference to Fig. 44.

On the lateral margins of the abdominal segments are a pair of bifid and trifid branched hairs on small papillae; dorsal margins of

these segments carry several single, bifid and trifid black simple hairs. Terminal segments (Fig. 45) on the eighth segment, the comb scales, 30 to 40 in number, are arranged in three irregular rows, each scale (Fig. 46) spatulate, the free margins carrying a fringe of fine hairs. Siphonal plume a tuft of six minutely pubescent hairs. Subsiphonal plume consists of a tuft of 8 to 9 pubescent hairs, much longer than the last, extending to more than half the length of the anal segment. Anal plume a tuft of 4 to 6 hairs, also pubescent, shorter than the last plume, longer than the first.

Siphon (Fig. 45) long, almost straight, slightly tapered, darker than the other terminal segments, apex darker still, arcus present. Index 5: 1. The pecten comprises a series of 8 to 10 strong and 3 to 5 smaller spines. The strong spines are equidistantly placed along the proximal third of the siphon; they are sharply pointed, arcuate

Fig. 45.—Terminal segments of C. pervigilans. larva. Fig. 46.—Comb Scale. Fig. 47.—Pecten scale from siphon.

at the base, and each bears three denticles on the basal half (Fig. 47). The 3 to 5 smaller spines are situated basad of the stronger spines, and are without denticles. Siphon plumes represented by four trifid and quadrifid branched hairs on the distal end, equidistantly spaced. Two or more small hairs on the terminal valves.

Anal segment not wholly invested with chitinous saddle, especially in the earlier instars. Ventral beard consists of 10 to 12 groups of long simple hairs. Dorsal hairs of 6 simple hairs arising from strong chitinous tubercles. Anal gills equal in length, elongated,