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.

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 basal area generally with a series of longitudinal lines, often very narrow or a single and oblique, sometimes interrupted, fascia.

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.

They have been found oligophagous or even monophagous on the following plant families: Asteraceae, Cannabaceae, Convolvulaceae, Cyperaceae, Poaceae, Fabaceae, Urticaceae.

In several species the larva constructs a silken tunnel inside the mine in which it hides when not feeding or when disturbed.

In colder climates species usually have one generation where hibernation takes place in the larval stage in a cocoon in or outside the mine.

In this case the moth runs on the upper side of a leaf and simultaneously makes very fast circling movements.