The dusky brocade (Apamea remissa) demonstrates quite well the problem with identifying some moths. Within the same species the colouring can be quite different from one individual to another. It can range from a greyish brown through, like this one, to a very dark brown partly depending on the specimens age as the colour does where off over time and if an individual manages to survive for a few weeks then it will be quite worn both structurally and pigmentally (is that a word?). Regardless of colour, though, the underlying pattern remains the same as does its physical features and so it remains possible to name a find in most cases.
A nocturnal moth that is rarely seen by day it flies as an adult from late May right through in to August. Not the same individuals of course but a succession of emerging insects. They feed on grasses and to they can turn up just about anywhere and they are quite common in gardens. The larvae feed on grasses to and over winter as a larvae before pupating and emerging in the early summer.