Stem
borer:
Larva an internal stem-borer. Pupation internal (Spencer, 1972b: 19).
Larva: The larvae of flies are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall.
Puparium: The puparia of flies are formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples).
Posterior spiracular plates adjoining, each with a regular ellipse
of 15 bulbs around a strong central horn (Spencer, 1972b: 19).
Adult: The adult and a recorded parasitoids are illustrated by Vikberg & Malinenin, 2012. Sahlbergia 18.2: 17-23
Comments:
Spencer (1966a: 21) and
Spencer (1972b: 16, 19,
111, 112) misidentifed British specimens of oligophaga as
dettmeri, which
is only known from Denmark (Spencer,
1990: 394).
The
adults are virtually indistinguishable from M. dettmeri (known
only on Centaurea jacea from Denmark) with the following
essential characters: frons not projecting above eye, orbital setulae
in 2 rows, those nearest eye margin reclinate, inner row proclinate;
eye with distinct pilosity in both male and female; mesonotum normally
faintly greenish; squamae pale, margin pale brown, fringe whitish
to ochrous; wing length normally about 3 mm (Spencer,
1990: 394).
Hosts in Great Britain and Ireland:
Hosts
elsewhere:
Time
of year - larvae: Currently unknown.
Time
of year - adults: May. Overwinters as puparium.
Distribution
in Great Britain and Ireland: Surrey (Banstead, Betchworth
and Walton Heath); Middlesex (Scratch Wood), Cambridgeshire (Chippenham
Fen), Derby (Miller's Dale), Denbighshire (Wrexham) and Perthshire (Killin)
(Spencer, 1972b: 19 (as dettmeri,
see also Spencer, 1990: 394).
Distribution
elsewhere: Holland, Germany (Spencer,
1990: 394), Belarus, Germany, Latvia and Lithuania (Fauna Europaea).
NBN Atlas links to known host species:
British and Irish Parasitoids in Britain and elsewhere:
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