How to identify Lepidoptera
This is too large a subject to be covered here but I will give a few tips and reminders.
Butterfly species are few in number but that does not mean that there in no scope for confusion. The whites need to be seen closely and even then it can be hard to distinguish between a small Large White and a large Small White. The two Pearl-bordered Fritillary species require very close examination especially of the underside markings. The blues are another group that can be tricky and again the underwing markings are the best way of being sure which species is involved. Female Common Blues are easily confused with the Brown Argus.
Macro-moths are often straight-forward but there are many difficult species. Remember that size and wing shape are important characters. Dissection is needed for some groups including the Pugs, November Moths, Common Rustic / Lesser Common Rustic, Dark Dagger / Grey Dagger, the Ear Moths and the Marbled Minor species aggregate.
Micro-moths are a challenging group and dissection is frequently essential. Please be very cautious about using the new book on micro-moths as it is not comprehensive.
In all cases it is advisable to check on both the North Wales status and the flight-time before coming to any conclusions.
I am prepared to determine specimens free of charge (but with no guarantee of success). The moths should be killed - put them in the freezer- and then dried by exposure to the air and packaged in small containers with wadding to prevent them rattling around. Alternatively, small waxed envelopes are an excellent way of storing moths without dislodging too many scales. The envelopes can be stacked loosely but compactly within a small box. Another very successful way of sending specimens is by using short lengths of clear plastic tube with cotton wool pushed in from each end and the moth in the middle. Get in touch if this offer is of interest.