Lucilia caesar


This blow fly is bright iridescent green though like all the 'greenbottles' is becomes more bronze with age. It is very similar to other Lucilia species but has just two pairs of acrostichal bristles behind the suture line on the thorax and a dark basicosta.

Similar Species

There are seven very similar Lucilia species that can be found in our region. They can only be separated by close examination of features such as bristles. L. caesar can be distinguished from the more common L. sericata by having only two pairs of post suture acrostichal bristles and a dark basicosta, but there are other Lucilia species with these features.

Identification difficulty
ID checklist (your specimen should have all of these features)
  • dark basicosta
  • presence of a coxopleural streak (see ID Aids above)
  • 2 pairs of acrostichal bristles behind the suture line on the thorax
  • males have a frons (between the eyes) that is narrower than the parafacialia (facial areas between the eyes and the antennae)
Identification aids

A key feature needed to identify Lucilia caesar is the presence of a coxopleural streak - a small and subtle pale, buff-coloured line on the side of the fly.

Lucilia caesar coxopleural streak

Recording advice

This can only be separated from other Lucilia species by microscopic examination.


Unlike its cousin the bluebottle, this species rarely comes into houses and is usually seen on flowers and vegetation, or sunning in a sheltered spot.

When to see it

April to October peaking in June.

Life History

The female lays her eggs on carcasses, seeking the soft parts that are shaded from the sun. Larvae live in carrion and also in wounds on living animals, eating away the flesh with alarming rapidity, and so can be a problem in sheep-rearing areas.

UK Status

Common and widespread in Britain.

VC55 Status

Common but under-recorded in Leicestershire and Rutland

Further Information

Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map

Species profile

Species group:
Records on NatureSpot:
First record:
14/10/2005 (Nicholls, David)
Last record:
25/10/2023 (Nicholls, David)

Total records by month

% of records within its species group

10km squares with records

The latest images and records displayed below include those awaiting verification checks so we cannot guarantee that every identification is correct. Once accepted, the record displays a green tick.

In the Latest Records section, click on the header to sort A-Z, and again to sort Z-A. Use the header boxes to filter the list.

Latest images

Latest records