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Agrodiaeuts thersites

Chapman's Blue

Field Notes

Valais, Switzerland, April 2010

Rhodope Mts, Greece, May 2004

Typical female with blue basal areas and orange submarginal patches

Valais, Switzerland, May 2005

Valais, Switzerland, July 2006

Valais, Switzerland, June 2006

Valais, Switzerland, July 2006

Vaud, Switzerland, July 2006

Vaud, Switzerland, July 2006

Var, France, May 2005

Valais, Switzerland, May 2005

Macedonia, Greece, July 2000

Macedonia, Greece, July 2000

Pelopennesos, Greece, June 2002

To all intents and purposes this species is identical to the Common Blue (Polyommatus icarus)... except for one vital feature: it lacks the black cell spot found on the underside forewing of icarus. It is much less variable than icarus, the males being always bright blue with violet tint and narrow black borders, the females nearly always mostly brown in the summer broods, mostly blue in spring.

There are some reports of occasional specimens of icarus lacking the cell spot, so resembling thersites very closely. Usually thersites is common so if there are several specimens without cell spots you can be certain of thersites. There is, allegedly, another feature that separates these species (ref. Lafranchis). It concerns the relative positions of the two small post discal spots on the underside forewings in space 2. This feature might hold true for France - see if you find anything constant elsewhere in the range.

I've found this species across its range from Morocco, Spain, France, Italy, Switzerland, Greece and Slovakia. It flies in Morocco in September and October in a possible 3rd brood. Elsewhere it is usually double brooded.

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