Vol 10 Part 14. An introduction to the immature stages of British Flies ...

eliably identified by the key in Pinder (1978). A typical pupa is illustrated (fig. 1121)
and a key to pupal exuviae is provided by Langton (1984).
Eggs are laid in a protective gelatinous matrix and each subfamily appears to have
a characteristic shape of egg and arrangement within the mass, e.g. linear type
(Orthocladiinae, Diamesinae); compact type- spherical, tear or fig-shaped, or
occasionally attached to a solid object by a gelatinous stalk (Tanypodinae,
Chironominae) (figs 980-982).
The life-histories ofChironomidae are reviewed by Oliver (1971) and a bibliography
of Chironomidae is provided by Fittkau et al. (1976). Keys to larvae and pupae are
provided by various authors in Wiederholm ( 1983, 1986). These are cited below, under
subfamilies. This comprehensive work will also eventually cover pupae and adults, and
reliable keys beyond genus are cited.
The subfamilies may be distinguished in the larval stage as follows (after Cranston
1982).
Antenna retractile into head capsule (fig, 53, an); ligula strongly developed (fig. 53.lg)
. . . . . . . . . . . . . . . . . . . . . . . Tanypodinae
Antenna not retractile; ligula not strongly developed . . . . . . . . . . . 2
2 Premandibles absent; procerci 8- 10 times as high as wide (fig. 59, pc) . . Polloaominae
Premandibles present (fig. 54, pm); procerci rarely more than 4 times as high as wide 3
3 Third antennal segment annulate (fig. 56) . . . . . . . . Diarwsiww (Diamesini)
Third antennal segment not annulate . . . . . . . . . . . . . . . . 4
4 Anterior part of labrum (fig. 54, la) with a transverse row of'scales' (fig. 57) . . . . .
. . . . . . . . . . . . . . . . . . . . Diamesiaar (Protanypini)
Labrum without this row of 'scales' . . . . . . . . . . . . . . . . 5
5 Ventral part of the mentum (fig. 54, m) expanded laterally to form ventromental plates which
are usually striated (fig. 55) . . . . . . . . . . . . . . Cllirooominae
Ventromental plates not striated . . . . . . . . . . . . . . . . . 6
6 Ventromental plates well developed, extending beyond mentum by at least half of the width
of the flattened mentum . . . . . . . . . . . . . . . Prodiamesinae
Ventromental plates smaller, never extending beyond mentum by as much as half width of
flattened mentum . . . . . . . . . . . . . . . . . . . . . . 7
7 Hypopharynx (fig. 54, h) with an apical group of elongate, serrate hairs (fig. 58) . . . .
. . . . . . . . . . . . . Tet.&togetoninae
Hypopharynx with a few shorter hairs . . . . . . . . . . . . Ortllocladiinae
Tanypodinae. Larvae of this subfamily are aquatic, may be red with haemoglobin,
and do not construct tubes or cases. They prey on small Crustacea, oligochaete worms
and often on the larvae of other Chironomidae. Adaptations to the predaceous habit
include the retractile antennae and rather long stilt-like pro legs, the latter giving rise to
a rapid jerky motion (fig. 65). The pupae resemble those of mosquitoes and are freeliving
active swimmers. Larvae of Tanypodinae are keyed (to genera) by Fittkau &
Roback (in Wiederholm, 1983: 33- 110).
Podonominae and Diamesinae. Larvae of these small subfamilies appear to be
generally adapted for life in cold conditions and are found in mossy mountain springs
and cold streams. Lasiodiamesa sphagnicola (Kieffer), however, favours wanner pools
in Sphagnum bogs. Larvae of Podonominae feed on diatoms, are free-living and very
strong swimmers (even as pupae). Larvae of Podonominae are keyed by Brundin (in
Wiederholm, 1983: 25- 31) and Diamesinae (to genera) by Oliver (in Wiederholm, 1983:
115-138).
Orthocladiinae. Some larvae of this subfamily are terrestrial, usually in moss covered
soil. Larvae of Bryophaenocladius have been reported as attacking the roots of greenhouse
plants, stored potatoes, mosses, liverworts and commercial lettuce crops and are
able to 'skip' like a cheese-skipper (Piophila) . I have seen larvae (probably Smittia sp.)
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