. Text book of zoology. Zoology. 276 Arthropoda. the thorax by a constriction. The 1 a r v se are invariably maggots, , the thoracic appendages are absent. Some, however, still possess a hard chitinised head furnished with eyes, antennee, and mouth-parts. In others on the contrary, the head is not well marked, eyes are absent, the antennse absent or very degenerate, the mouth-parts represented by a pair of darkly-coloured chitinous hooks (mandibles ?). The larvee live in water, in decaying substances, in or upon plants, or as parasites. In those Diptera whose larvse have well developed hea
. Text book of zoology. Zoology. 276 Arthropoda. the thorax by a constriction. The 1 a r v se are invariably maggots, , the thoracic appendages are absent. Some, however, still possess a hard chitinised head furnished with eyes, antennee, and mouth-parts. In others on the contrary, the head is not well marked, eyes are absent, the antennse absent or very degenerate, the mouth-parts represented by a pair of darkly-coloured chitinous hooks (mandibles ?). The larvee live in water, in decaying substances, in or upon plants, or as parasites. In those Diptera whose larvse have well developed heads, the pup« are like those of the Lepidoptera, the appendages lying close to the body; in those with " headless " grubs the pupae remain within the last hardened larval skin (coarctate pupee). 1. Midges (Nemocera) are usually slender with long antennae, which in the males are often furnished with long hairs. The wings are narrow, the legs long and thin. To mention a few forms: Gnats (Culex) antennae of fourteen joints, with long hairs in the male; maxillary palps in the male longer than the proboscis; the females alone possess mandibles, and stab and suck blood: the larvae are aquatic; they have only two stigmata, situated on a terminal process (respiratory tube); the pupa is motile, and has two upright respiratory tubes at the front end of the body; both larvae and pupae usually hang suspended by these respiratory tubes from the surface of the water. The Daddy-long-legs or Crane-flies (Tipula) a,re a c h large Midges, the larvae of which live in meadows, or in rotten wood. The Gall- flies {Cecidomyia, etc.) are very small delicate forms, the larvae of which, like the Cynipidae, frequently live in gaUs (one of these for in- stance, C. fagi, lives in the well-known pointed gall of beech leaves); many species, however, do not form galls, but the larvae are found in living or dead plants. In some species of this group, paedogenesis is known to occur (see p. 246). The S
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