Heath fritillaries have a wingspan of 39–47 mm.
The upperside is predominantly dark brown and orange brown, with the orange-brown spots delineated by dark brown (along and across the wing veins); there is a white fringe to the wings through which the dark brown extends.
The upperside of the body is a similar dark brown to the colour on the wing, and the base of both wings is dark brown.
The underside shows bands of red and (off-)white, again with each vein dark brown and each colour delineated by dark brown.
The pattern of white spots at the base of the hindwing (visible at rest) is diagnostic for identification.

These wing patterns are very similar to the appearance of Melitaea cinxia.
However, the dark brown bands on underside of the wings are more distinct in the health fritillary than in M. cinxia.
Heath fritillaries have a wingspan of 39–47 mm. The upperside is predominantly dark brown and orange brown, with the orange-brown spots delineated by dark brown (along and across the wing veins); there is a white fringe to the wings through which the dark brown extends. The upperside of the body is a similar dark brown to the colour on the wing, and the base of both wings is dark brown. The underside shows bands of red and (off-)white, again with each vein dark brown and each colour delineated by dark brown. The pattern of white spots at the base of the hindwing (visible at rest) is diagnostic for identification.
These wing patterns are very similar to the appearance of Melitaea cinxia. However, the dark brown bands on underside of the wings are more distinct in the health fritillary than in M. cinxia.
Heath fritillary