The leaf and stem mines of British flies and other insects
 

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds

  

Chromatomyia milii (Kaltenbach, 1864)
[Diptera: Agromyzidae]

Phytomyza milii Kaltenbach, 1864. Verh. naturh. Ver. preuss. Rheinl. 21: 248
Phytomyza milii Kaltenbach, 1864; Hendel, 1935. Fliegen palaearkt. Reg. 6(2): 431
Phytomyza intermedia Spencer, 1957a. Ent. Gaz. 8: 21-2
Phytomyza milii Kaltenbach, 1864; Griffiths, 1964. Ent. Meddr. 32: 405
Phytomyza milii Kaltenbach, 1864; Spencer, 1972b. Handbk ident. Br. Ins. 10(5g): 92, 93 (figs 322-3) 94, 95
Phytomyza milii Kaltenbach, 1864; Spencer, 1976. Fauna ent. Scand. 5(1): 447-9, figs 762-9.
Chromatomyia milii (Kaltenbach, 1864); Spencer, 1990. Host specialization in the World Agromyzidae (Diptera) : 356, 377, 378 (figs 1431-2), 405.
Mine of Chromatomyia milii on Holcus lanatus. Image: Willem Ellis (Source: Bladmineerders van Europa)
Mine of Chromatomyia milii on Holcus lanatus
Image: © Willem Ellis (Bladmineerders van Europa)

Leaf-miner: A substantial linear mine. Pupation internal; posterior spiracles projecting through the epidermis (Spencer, 1976: 449).

Elongated, shallow, upper-surface or lower-surface blotch, not infrequently several in one leaf. Frass in strings or pearl chains. Pupation within the mine (Bladmineerders van Europa)

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.

The larva is described by de Meijere (1926), Dempewolf (2001: 204) and illustrated in Bladmineerders van Europa.

Chromatomyia milii larva, lateral
Chromatomyia milii larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

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 spiracles elongated (Spencer, 1972b: 95). The bifid anterior spiracles of the puparium penetrate the epidermis; the posterior spiracula are dagger-shaped, elongated and curved, and are anchored in the leaf tissue (Bladmineerders van Europa)

Chromatomyia milii larva, lateral
Chromatomyia milii larva, dorsal
Image: © Willem Ellis (Bladmineerders van Europa)

Hosts in Great Britain and Ireland:

Poaceae        
Hierochloe       Spencer, 1972b: 123
Holcus mollis Creeping Soft-grass   Rotheray, 1987
Hordeum       Spencer, 1972b: 95, 124
Hordeum vulgare Six-rowed Barley   Spencer, 1972b: 124
Milium       Robbins, 1991: 141
Milium effusum Wood Millet British Wild Flowers by John Somerville et al. Mines in BMNH
Milium effusum Wood Millet British Wild Flowers by John Somerville et al. Spencer, 1972b: 95, 124
Poa annua Annual Meadow-grass British Wild Flowers by John Somerville et al. Spencer, 1972b: 124
Poa trivialis Rough Meadow-grass British Wild Flowers by John Somerville et al. Spencer, 1972b: 124

Hosts elsewhere:

Poaceae        
Agrostis       Spencer, 1990: 354
Agrostis       Bladmineerders van Europa
Avena       Bladmineerders van Europa
Brachypodium sylvaticum False Brome British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Catabrosa aquatica Whorl-grass British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Festuca       Bladmineerders van Europa
Hierochloe       Spencer, 1976: 447
? Hierochloe       Spencer, 1990: 354
Hierochloe odorata Holy-grass British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Holcus       Spencer, 1990: 354
Holcus lanatus Yorkshire-fog British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Holcus mollis Creeping Soft-grass   Bladmineerders van Europa
Hordeum       Spencer, 1976: 447
Hordeum       Bladmineerders van Europa
Lolium       Bladmineerders van Europa
Milium       Spencer, 1990: 356
Milium effusum Wood Millet British Wild Flowers by John Somerville et al. Spencer, 1976: 447
Milium effusum Wood Millet