Phyllonorycter adderis is a moth of the Gracillariidae family. It is found in south-western Rwanda. The habitat consists of montane wet, closed canopy forests at an altitude of about 1,800 metres.
The length of the forewings is 2.85–2.96 mm. The forewing ground colour is ochreous with white markings. The hindwings are dark grey with a long fringe of the same shading as the hindwing. Adults are on wing in August.
The larvae feed on Urena lobata. They mine the leaves of their host plant. The mine has the form of a semi-transparent tentiform mine which is made on the underside of the leaf. Several mines can be present on a single leaf.
Phyllonorycter adderis Wikipedia
The specific epithet is derived from Latin addere (meaning to append) and refers to the long appendical cucullus on the valve.