Cosmopterixspecies are very small to small moths with a forewing length of 2.9-6.5 mm. Head smooth-scaled, rather long and narrow caused by the large and bent scales on the vertex; frons distinctly lighter than vertex, from vertex to neck tufts often a median and/or two lateral white lines; antenna three-quarters to four-fifths of the length of forewing, often slightly serrate distally, and generally with a white, often partly interrupted, anterior line and several white sections in the apical part; labial palpus cylindrical, porrect, apical segment strongly angled upwards and often reaching well above the head. Thorax with or without a median white line, tegulae often lined white inwardly. Forewing narrowly lanceolate with long and very narrowly protruding apex and usually with a very characteristic yellow or orange fascia beyond the middle, this fascia bordered by tubercular metallic fasciae or spots; basal area with a metallic fascia or spots or with three to six longitudinal lines of different length, cilia concolorous around apex, paler towards dorsum. Hindwing almost linear, less than half the width of forewing and acutely pointed, from pale yellow to dark grey, without markings, cilia concolorous without ciliary lines. The forewing can generally be divided into three parts: The basal area from base to middle of wing, followed by the broad transverse fascia and beyond this the apical area. The basal area generally with a series of longitudinal lines, often very narrow or a single and oblique, sometimes interrupted, fascia. The lines are mentioned from costa to dorsum as the costal, the subcostal, the medial, the subdorsal and the dorsal line. The transverse fascia is strikingly coloured from pale yellow to orange and in combination with the narrow wings it makes the species of Cosmopterix and Pebobs easy recognisable. The transverse fascia is always more or less edged on both sides by fasciae or spots. These fascia or spots consist of very strikingly silver or golden metallic coloured tubercular scales. Some species partly or completely lack the yellowish colour of the transverse fascia. However, the presence of the ‘fascia’ can be observed by the lining tubercular fasciae or spots. The transverse fascia can be edged by a combination of inner and outer fasciae and/or by an inner and outer (sub)costal and (sub)dorsal spots. Sometimes the (sub)costal and (sub)dorsal spots are situated inside the transverse fascia. The apical area is generally concolorous with the basal area, but occasionally the colouration differs. In the centre or on the dorsal side of the apical area is a longitudinal apical line, running from the transverse fascia to apex of forewing. This line is often interrupted or only present as one or more dots or streaks. Markings of the costal and dorsal cilia of the forewing are as follows: a white streak from outer costal spot in almost all of the species, a white streak or spot connected to the apical line is very common,and occasionally there is a white streak from outer dorsal spot. For identification of the species by the external features, mainly the markings of the head, thorax and forewing are of diagnostic importance. Wing venation with 12 veins in forewing and 7 veins in hindwing. Forewing with Sc and R1-R4 to costa; R5 directing towards the narrow tip; M1-CuA2 to termen; CuP very weak and not reaching termen; 1A+2A with basal fork, to dorsum. Hindwing Sc and Rs to costa; M1-CuA2 to termen; veins often not fully developed due to the narrow shape of the hindwing.[2]