Geometra virgularia Hübner, [1799] The small dusty wave (Idaea seriata) is a moth of the family Geometridae first described by Franz von Paula Schrank in 1802.

The species is very small (wingspan 19–21 mm) and is probably one of the least striking members of the whole family, being basically grey with all markings indistinct apart from the black discal spot typical of the genus.

The median shade is thicker, not rarely rather strongly developed, often, on the contrary, quite obsolete even in forms in which the lines are sharply marked; it usually touches the cell-spot on the forewing and is always proximal to it on the hindwing.

The postmedian is fine and grey, not itself conspicuous but marked with strong, coarse black spots on the veins; it stands rather near the distal margin and is incurved between the radials, then outcurved; the form of this line is best shown on the right forewing in our figure and may be compared to that which occurs in a higher degree of development in calunetaria.

; distal marginal line consisting of a series of black dashes of variable thickness, sometimes almost obsolete; fringe with more or less strong dark dots at base, opposite the vein-ends.