themselves to the bark and leaves of trees, on which they deposit their eggs, covering them with their bodies. Coccus.

Plant-lice or Aphites. Antennæ conspicuous, elongate, seven-jointed; fore wings deflexed, meeting over the back with a straight suture; hind wings much smaller and shorter; all the wings membranaceous; legs of uniform structure, not formed for leaping; tarsi two-jointed. Infest all vegetables, sucking the sap: reproduction without union of sexes for many generations. Aphis.

Moth-blights or Aleyrodites. Larva oval, flat and scalelike. Pupa changes within the skin of the larva; is quiescent. Imago with the antennæ filiform, conspicuous and sixjointed; wings equally developed, both as to length and breadth, covered with a white, mealy substance, like the scales of Lepidoptera; legs of uniform structure, not formed for leaping. Sits on the under-side of the leaves of the plants on which the larva feeds. Aleyrodes.

Neuroptera.-The metamorphosis of the seventh class, Neuroptera, differs in its different orders. Larva with strong corneous mandibles moving horizontally, and six articulate feet, situated in pairs on the second, third, and fourth segments; prehensile feet none. Pupa various. Imago usually with the organs of the mouth perfect; the wings fully developed, and resembling net-work.

Pearl-flies or Perlites. Larva with long, filiform, multiarticulate antennæ; strong, corneous, masticatory mandibles; telum furnished with two long, setiform appendages; active, carnivorous, aquatic. Pupa isomorphous. Imago with long, filiform, multi-articulate antennæ; strong, corneous, masticatory mandibles; wings fully and equally developed, reticulated, recumbent; the hind wings folded; tarsi three-jointed. Inhabits the banks of running waters, and is a very favourite food of fish; flight nocturnal. Perla, Isogenus, Chloroperla, Nemoura.

Snake-flies or Raphidiites. Larva with filiform antennæ, and corneous, masticatory mandibles; active. Inhabits and feeds on decayed wood. Pupa isomorphous. Imago with moniliform antennæ; corneous, masticatory mandibles ; head large, porrected; prothorax elongate; wings uniformly and fully developed, recumbent, deflexed, not folded, beautifully reticulated; tarsi four-jointed; telum with a seta: flight diurnal, in the sunshine. Raphidia.

Lace-winged flies or Hemerobiites. Larva with filiform antennæ; mandibles and maxillæ prominent, corneous; sacciferous, carnivorous. Inhabits the leaves of vegetables. Pupa necromorphous; changes within the sack formed by the larva. Imago with long, moniliform antennæ; mandibles corneous, masticatory; wings fully and equally developed, not folded, beautifully reticulated, deflexed; tarsi five-jointed; smells fetid; flies mòstly in the evening. Hemerobius, Chrysopa, Osmylus.

Stone-flies or Phryganiites. Larva with short antennæ ; mandibles corneous, masticatory; sacciferous, aquatic. Pupa necromorphous, changes in the sack formed by the larva.

Imago with very long, multi-articulate, filiform antennæ; mandibles and maxilla obsolete; fore wings deflexed, very hairy; hind wings ample, much folded longitudinally, not so hairy; tarsi five-jointed. Inhabits the neighbourhood of water; flies in the evening and during the night, and is a favourite food of fish. Phryganea.

Caddew-flies or Ephemerites. Larva with long filiform antennæ; mandibles corneous, masticatory; legs six, articulate; aquatic, carnivorous. Pupa isomorphous. Imago with short concealed antennæ ; mandibles and maxillæ obsolete; fore wings fully developed; hind wings small or obsolete; all the wings beautifully reticulated, erect, and meeting above the back; tarsi four-jointed; telum furnished with long setiform appendages: flight in the evening, in

company, rising and falling, and is the favourite food of fish. Ephemera, Baëtis, Cloëon.

Scorpion-flies or Panorpites. Larva and pupa unknown. Imago with long, filiform, multi-articulate antennæ ; mandibles and maxillæ corneous, produced into a beak; wings of equal development, horizontally recumbent on the back; tarsi five-jointed; telum armed with an appendage resembling a lobster's claw: flight weak, of short duration, diurnal. Inhabits abundantly the woods and hedges of England throughout the summer. Panorpa.

Dragon-flies or Libellulites. Larva with short antennæ ; mandibles corneous, masticatory; labium very elongate, jointed and remarkable, being furnished with predatory, acute, mandibuliform palpi; aquatic, carnivorous. Pupa isomorphous. Imago with minute antennæ nearly concealed; mandibles strong, corneous, masticatory; labium of moderate proportions; wings of uniform development, beautifully reticulated, porrected laterally or meeting vertically above the back; tarsi three-jointed; flight rapid, well sustained; active, carnivorous. Agrion, Libellula, Æschna,

represented at page 199, the central figure.

Aberrant Orders.-Ticklers or Thripsites. Larva resembles the perfect insect, but has a softer body, with the meso- and metathorax distinct; the mouth is almost similar to that of the imago, but the antennæ and legs are shorter; there are no simple eyes, and the compound are replaced by conglomerate eyes. Pupa resembles the perfect insect, but the articulation of the limbs is obscured by a film, and the wings are enclosed in short fixed sheaths: the antennæ are turned back on the head, and the insect, though it moves about, is much more sluggish than in the other states. Imago having the parts of the mouth united to form a short conical sucker, more fleshy than horny and not retractile; the labium has the usual parts, the labium, properly

so called, being the longest; the ligula is sometimes prolonged between the labial feelers, equalling them in length, at others it does not reach beyond the base of these organs; the labial feelers are short and three-jointed; the maxillæ are somewhat triangular, with their lacinia acute the maxillary feelers are distinct and two- or three-jointed; the galea is obsolete; the mandibles are elongate and setiform, with their base flattened and dilated; the antennæ are somewhat moniliform and usually eight-jointed; the eyes are lateral and oval; the ocelli three, and situated in a triangle between the eyes; the prothorax is large and flat, the meso- and metathorax are so closely soldered together that the division is scarcely to be traced; the fore and hind wings are alike, long, narrow, delicate, generally nerveless and fringed with long ciliæ; the tarsi are twojointed and without claws. Inhabits flowers, leaves, and the bark of trees. Thrips.

Bee-parasites or Stylopites. Larva apod, with a corneous head; inhabits the bodies of wasps and bees in the perfect state, the head of the larva projecting between the abdominal segments of the bee. Pupa changes in the same situations. Imago with elongate, linear mandibles, and minute maxillæ, but large maxillary feelers; the antennæ have but few joints, and these are of very irregular form: there are two tippet-like appendages very near the head, and two large membranaceous wings, by some supposed to be analogous to the wings of Diptera or the fore wings, by others to those of Coleoptera or the hind wings; the question is one of great interest, and its solution is reserved for more able insect-anatomists than have hitherto dissected this curious creature. The perfect insect flies in the sunshine, occasionally settling on twigs and leaves, on which it runs rapidly, vibrating its tippets and wings; the tarsi are twothree- or four-jointed. Stylops, Elenchus, Halictophagus.

Fleas or Pulicites. Larva long, slender, wormlike and without feet, composed of thirteen segments, the last having two hooks; inhabits the young of quadrupeds and birds, particularly of pigeons in a domesticated state, on the blood of which it probably feeds. Pupa quiescent, necromorphous, changes in a little silken cocoon, in which it remains from eleven to sixteen days. Imago with the antenna many-jointed, usually concealed in cavities of the skull, but capable of being erected at the pleasure of the insect; the parts of the mouth are nearly as in Diptera; eyes simple; legs long; tarsi five-jointed. Inhabits all countries, sucking the blood of man and animals. Pulex.