The larvae of the fly Chromatomyia autumnalis mine the leaves of various thistles (Cirsium) and also some knapweeds (Centaurea). The mine is full depth, greenish, usually linear, which is usually upper surface and doubles back on itself. The pupa is metallic black and the anterior spiracles protrude through the lower epidermis.

See the National Agromyzidae Recording Scheme webpage for this species for further details of puparium and adult insect.

Chromatomyia spinaciae can only be separated by larval and puparium features. The puparium of Chromatomyia spinaciae is white whereas Chromatomyia autumnalis is black.

ref.: Warrington, B.P. (2023).  Chromatomyia autumnalis. Accessed at https://agromyzidae.co.uk/species/agromyzidae/phytomyzinae/phytomyza/ph… on 13/12/2023)

Leafmine Adult

Adult: Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Leafmine: this species can only be safely recorded if larva or puparium are present and can be examined.

Wherever the larval foodplants occur.

Click on the 'further details' link in the 'Description' section above.  Then click on the Phenology tab which will provide phenology details for both adult and larval stages.

The tenanted leafmine is most likely to be found between October and December.

In Britain this species is classed as Nationally Scarce A.

Warrington, B. P. 2022. A provisional review of the status of Agromyzidae in Great Britain & Northern Ireland

Rarely recorded in Leicestershire and Rutland.