Essex emerald

The Essex emerald (Thetidia smaragdaria) is a moth of the Geometridae family . It is distributed throughout the Palearctic region with records from many European countries. The British subspecies Thetidia smaragdaria maritima was last seen in 1991. In 2004 the first record from Sweden was made. But they are still an ongoing Subspecies At the nature reserve in Kent, United Kingdom

The wingspan is 27–35 mm. There is one generation per year with adults on wing from mid June to mid July.

The larvae feed on Artemisia maritima and Achillea millefolium. Larvae can be found from July to June the following year. It overwinters in the larval stage.