About 170.000 species of Lepidoptera have been described, although this number of is only an estimate, as the majority of names have not been catalogued in a systematic way. The numbers of described species and the estimated numbers still to be described are shown in the following table:
| Taxon | Known Species | Lower estimate | Higher estimate |
| Primitive groups | 10.000 | 15.000 | 20.000 |
| Gelechioidea | 24.000 | 60.000 | 100.000 |
| Tortricoidea | 9.150 | 15.000 | 20.000 |
| Pyraloidea | 16.000 | 30.000 | 30.000 |
| Rhopalocera | 17.000 | 18.000 | 20.000 |
| Geometroidea | 22.500 | 30.000 | 45.000 |
| Noctuoidea | 70.000 | 100.000 | 150.000 |
| Rest | 10.000 | 15.000 | 20.000 |
| Total | 178.650 | 283.000 | 405.000 |
| To be described | 108.850 | 228.850 | |
|---|---|---|---|
An estimated 100.000-250.000 species remain to be discovered and described. A large number of these are already in collections, but widespread collecting is still needed. Europe has the best known fauna, with almost all species already discovered and described. For many groups, especially in the so-called "micro-moths", the faunas of Africa and South America are almost unknown.
Recently there has been a call for more efficient methods for species discovery and description. LEPSYS.eu will help in developing new methods, including exploratory DNA "barcoding". LEPSYS.eu will also support new initiatives on web-based species descriptions and registration of new names (e.g. the EDIT programme).